Overall Green alert Tropical Cyclone for SEBASTIEN-19
in Portugal, Ireland, United Kingdom,

Global Telecommunication Service

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2019-11-25 02:34


Original Message :

WTNT45 KNHC 250232
TCDAT5

Post-Tropical Cyclone Sebastien Discussion Number 23
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Sun Nov 24 2019

Sebastien has lost its tropical characteristics this evening. The
deep convection has decoupled from the low-level circulation, and
these features are now separated by a distance of 100 n mi and
increasing. Two partial ASCAT passes revealed that the surface low
is becoming stretched out, and there is some evidence of a boundary,
possibly a front, extending northeast from the center. Furthermore,
recent observations from Corbo and Flores islands in the Azores
indicated a slight temperature decrease as the center passed by to
the north of those islands, suggesting that a weak cold front is
associated with the the cyclone. Based on all of these data, there
is high confidence that Sebastien has transitioned to an
extratropical cyclone. The initial advisory intensity is 50 kt which
is based on 47 kt winds sampled by the scatterometer and a
subjective intensity estimate from TAFB.

Post-tropical cyclone Sebastien is moving northeastward at 35 kt,
embedded in the strong flow to the southeast of a mid- to upper-
level trough. This motion, and the cyclone's current intensity, is
expected to persist for the next day or so, before the cyclone
merges with a higher-latitude low.

The cyclone will likely bring gusty winds and heavy rains to
portions of the Azores through Monday morning. Please see products
issued by the Portuguese Institute for the Sea and the Atmosphere
(IPMA) for more details.

Additional information on this system can be found in:

High Seas Forecasts issued by Meteo France under WMO header FQNT50
LFPW and on the web at
www.meteofrance.com/previsions-meteo-marine/bulletin/grandlarge/
metarea2.

FORECAST POSITIONS AND MAX WINDS

INIT 25/0300Z 41.0N 28.9W 50 KT 60 MPH...POST-TROP/EXTRATROP
12H 25/1200Z 43.6N 22.7W 50 KT 60 MPH...POST-TROP/EXTRATROP
24H 26/0000Z 48.1N 14.2W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 26/1200Z...MERGED WITH ANOTHER LOW

$$
Forecaster Latto

>

2019-11-25 02:33


Original Message :

WTNT35 KNHC 250231
TCPAT5

BULLETIN
Post-Tropical Cyclone Sebastien Advisory Number 23
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Sun Nov 24 2019

...SEBASTIEN NO LONGER A TROPICAL CYCLONE...
...THIS IS THE LAST ADVISORY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...41.0N 28.9W
ABOUT 230 MI...370 KM NNW OF THE AZORES
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 40 MPH...65 KM/H
MINIMUM CENTRAL PRESSURE...993 MB...29.33 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the Azores should monitor the progress of the
remnants of Sebastien.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Post-Tropical Cyclone
Sebastien was located near latitude 41.0 North, longitude 28.9 West.
Sebastien is moving toward the northeast near 40 mph (65 km/h) and
this motion is expected to continue for the next day or so.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Post-tropical cyclone Sebastien should maintain its intensity
before merging with another low during the next day or two.

Gale-force winds extend outward up to 220 miles (350 km)
from the center.

The estimated minimum central pressure is 993 mb (29.33 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: The cyclone is expected to bring gusty winds and
rain to the Azores through Monday morning. Please see products
issued by the Portuguese Institute for the Sea and the Atmosphere
(IPMA) for more information.

SURF: Swells generated by Sebastien are expected to affect the
Azores during the next couple of days. These swells are likely to
cause life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
This is the last public advisory issued by the National Hurricane
Center on Sebastien.

Additional information on this system can be found in:

High Seas Forecasts issued by Meteo France under WMO header FQNT50
LFPW and on the web at:
www.meteofrance.com/previsions-meteo-marine/bulletin/grandlarge/
metarea2

$$
Forecaster Latto

>

2019-11-25 02:33


Original Message :

WTNT25 KNHC 250231
TCMAT5

POST-TROPICAL CYCLONE SEBASTIEN FORECAST/ADVISORY NUMBER 23
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0300 UTC MON NOV 25 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE AZORES SHOULD MONITOR THE PROGRESS OF
POST-TROPICAL CYCLONE SEBASTIEN.

POST-TROPICAL CYCLONE CENTER LOCATED NEAR 41.0N 28.9W AT 25/0300Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 35 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 993 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 50SE 0SW 0NW.
34 KT....... 90NE 170SE 190SW 90NW.
12 FT SEAS.. 90NE 240SE 420SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 41.0N 28.9W AT 25/0300Z
AT 25/0000Z CENTER WAS LOCATED NEAR 40.0N 30.8W

FORECAST VALID 25/1200Z 43.6N 22.7W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 50SE 0SW 0NW.
34 KT... 90NE 170SE 190SW 90NW.

FORECAST VALID 26/0000Z 48.1N 14.2W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 50SE 0SW 0NW.
34 KT...110NE 190SE 190SW 70NW.

FORECAST VALID 26/1200Z...MERGED WITH ANOTHER LOW

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 41.0N 28.9W

THIS IS THE LAST FORECAST/ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON SEBASTIEN. ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE
FOUND IN HIGH SEAS FORECASTS ISSUED BY METEO FRANCE UNDER WMO HEADER
FQNT50 LFPW.

$$
FORECASTER LATTO

>

2019-11-24 21:02


Original Message :

WTNT45 KNHC 242059
TCDAT5

Tropical Storm Sebastien Discussion Number 22
NWS National Hurricane Center Miami FL AL202019
500 PM AST Sun Nov 24 2019

Sebastien is gradually losing tropical characteristics. Satellite
images show a large shield of relatively cold cloud tops on the
north side of the system and in a band that extends from east of the
center south-southwestward. This cloud pattern resembles an
extratropical cyclone. However, satellite images and microwave data
also show a small area of deep convection lingering over the center,
which is why the system is still designated a tropical cyclone for
now. That being said, it is still not clear that the surface
circulation of the storm is well defined. Hopefully, ASCAT data
later this evening can help assess the structure of the circulation.
The initial intensity is held at 55 kt, which is in agreement with
the most recent SATCON estimate from CIMSS at the University of
Wisconsin.

Sebastien is expected to slowly weaken as it remains in very strong
wind shear conditions while moving over progressively colder
waters. FSU phase-analysis diagrams from the global models all show
Sebastien becoming fully extratropical overnight, and the NHC
forecast follows that scenario. The extratropical low is expected
to merge with another cyclone in 24 to 36 hours. It is also
possible, as alluded to above, that Sebastien could open into a
trough before then.

Sebastien is racing toward the east-northeast ahead of a cold front,
and the initial motion estimate is 060/34 kt. This continued
heading at an even faster rate is expected within the fast
mid-latitude flow until the cyclone dissipates.

Regardless of whether it is a tropical cyclone, extratropical
cyclone, or a remnant trough, Sebastien or its remnants will likely
bring gusty winds and heavy rains to portions of the Azores through
Monday morning. Please see products issued by the Portuguese
Institute for the Sea and the Atmosphere (IPMA) for more
information.


FORECAST POSITIONS AND MAX WINDS

INIT 24/2100Z 39.2N 32.5W 55 KT 65 MPH
12H 25/0600Z 42.2N 25.7W 55 KT 65 MPH...POST-TROP/EXTRATROP
24H 25/1800Z 46.3N 17.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 26/0600Z...MERGED WITH ANOTHER EXTRATROPICAL LOW

$$
Forecaster Cangialosi

>

2019-11-24 21:01


Original Message :

WTNT35 KNHC 242058
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 22
NWS National Hurricane Center Miami FL AL202019
500 PM AST Sun Nov 24 2019

...SEBASTIEN OR ITS REMNANTS EXPECTED TO BRING GUSTY WINDS AND RAIN
TO PORTIONS OF THE AZORES THROUGH MONDAY MORNING...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...39.2N 32.5W
ABOUT 310 MI...495 KM WNW OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 39 MPH...63 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the Azores should monitor the progress of Sebastien.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Sebastien was
located near latitude 39.2 North, longitude 32.5 West. Sebastien is
moving toward the east-northeast near 39 mph (63 km/h). An even
faster motion toward the northeast or east-northeast is expected
during the next day or so. On the forecast track, the center of
Sebastien will pass near the western Azores tonight.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. A slow decrease in the maximum winds is expected during the
next day or so. Sebastien is forecast to become post-tropical
by early Monday, and it could degenerate into a trough of low
pressure at any time during the next couple of days. Regardless of
status, Sebastien or its remnants will likely continue to produce
tropical-storm-force winds for at least a couple more days.

Tropical-storm-force winds extend outward up to 140 miles (220 km)
from the center.

The estimated minimum central pressure is 994 mb (29.36 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: Sebastien or its remnants are expected to bring
gusty winds and rain to the Azores through Monday morning. Please
see products issued by the Portuguese Institute for the Sea and the
Atmosphere (IPMA) for more information.

SURF: Swells generated by Sebastien are expected to affect the
Azores during the next couple of days. These swells are likely to
cause life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Cangialosi

>

2019-11-24 21:01


Original Message :

WTNT25 KNHC 242058
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
2100 UTC SUN NOV 24 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE AZORES SHOULD MONITOR THE PROGRESS OF SEBASTIEN.

TROPICAL STORM CENTER LOCATED NEAR 39.2N 32.5W AT 24/2100Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR 60 DEGREES AT 34 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 0NE 40SE 30SW 0NW.
34 KT....... 90NE 120SE 90SW 60NW.
12 FT SEAS.. 90NE 240SE 420SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 39.2N 32.5W AT 24/2100Z
AT 24/1800Z CENTER WAS LOCATED NEAR 38.4N 34.3W

FORECAST VALID 25/0600Z 42.2N 25.7W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 40SE 30SW 0NW.
34 KT... 70NE 160SE 160SW 60NW.

FORECAST VALID 25/1800Z 46.3N 17.0W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 40SE 40SW 0NW.
34 KT...100NE 240SE 240SW 70NW.

FORECAST VALID 26/0600Z...MERGED WITH ANOTHER EXTRATROPICAL LOW

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 39.2N 32.5W

NEXT ADVISORY AT 25/0300Z

$$
FORECASTER CANGIALOSI

>

2019-11-24 15:59


Original Message :

WTNT82 EGRR 241558

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 1200UTC 24.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 36.4N 38.9W

ATCF IDENTIFIER : AL202019

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 24.11.2019 0 36.4N 38.9W 995 42
0000UTC 25.11.2019 12 39.9N 30.9W 990 48
1200UTC 25.11.2019 24 44.3N 21.6W 979 47
0000UTC 26.11.2019 36 48.5N 13.5W 973 47
1200UTC 26.11.2019 48 51.4N 10.6W 961 46
0000UTC 27.11.2019 60 50.9N 7.1W 966 39
1200UTC 27.11.2019 72 CEASED TRACKING


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

MET OFFICE, EXETER, UK

TOO 241557

>

2019-11-24 15:59


Original Message :

WTNT80 EGRR 241557

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 12UTC 24.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 36.4N 38.9W

ATCF IDENTIFIER : AL202019

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 24.11.2019 36.4N 38.9W MODERATE
00UTC 25.11.2019 39.9N 30.9W MODERATE INTENSIFYING SLIGHTLY
12UTC 25.11.2019 44.3N 21.6W STRONG INTENSIFYING SLIGHTLY
00UTC 26.11.2019 48.5N 13.5W STRONG INTENSIFYING SLIGHTLY
12UTC 26.11.2019 51.4N 10.6W STRONG INTENSIFYING SLIGHTLY
00UTC 27.11.2019 50.9N 7.1W STRONG WEAKENING SLIGHTLY
12UTC 27.11.2019 BELOW TROPICAL STORM STRENGTH


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

BULLETINS ARE NOW AVAILABLE WHICH PROVIDE EXPLICIT GUIDANCE
ON CENTRAL PRESSURE AND MAXIMUM WIND SPEED.
FOR FURTHER INFORMATION CONTACT TROPICAL_CYCLONES@METOFFICE.GOV.UK

MET OFFICE, EXETER, UK

TOO 241557

>

2019-11-24 14:43


Original Message :

WTNT45 KNHC 241441
TCDAT5

Tropical Storm Sebastien Discussion Number 21
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Sun Nov 24 2019

It is not clear if Sebastien is a closed cyclone at the surface. The
fast forward motion of the cyclone (28 kt) may have caused it to
open into a trough of low pressure. The ship MSC Beijing (DFDE2)
recently reported northwest winds about 70 n mi north-northeast of
the cyclone's estimated center, and it has been difficult to
identify easterly winds in visible imagery this morning. That said,
ASCAT data was inconclusive regarding the state of Sebastien's
circulation and the system is still producing some deep convection
near its center. AMSU data at 1135 UTC also indicated that Sebastien
still has a weak warm core. For those reasons, it appears prudent to
maintain advisories at this time.

As mentioned above, Sebastien is moving very quickly northeastward
and it should accelerate in that direction during the next 24 h.
This is shown by all of the dynamical models which are finally in
decent agreement. Based on simulated satellite imagery, it appears
that the cyclone will continue to produce central deep convection
for the next 12 h or so, and extratropical transition is forecast to
finish within 24 h. Although an extratropical point is shown at 36 h
for continuity purposes, in reality Sebastien will more likely open
into a trough of low pressure, given the forecast forward motion of
nearly 40 kt relative to its 50 kt forecast intensity at this time
tomorrow. This could happen at any time.

Regardless of whether it is a tropical cyclone, extratropical
cyclone, or a remnant trough, Sebastien or its remnants will likely
bring gusty winds and heavy rains to portions of the Azores later
today and tonight. Please see products issued by the Portuguese
Institute for the Sea and the Atmosphere (IPMA) for more
information.


FORECAST POSITIONS AND MAX WINDS

INIT 24/1500Z 37.4N 37.0W 55 KT 65 MPH
12H 25/0000Z 39.8N 31.0W 55 KT 65 MPH
24H 25/1200Z 43.8N 22.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 26/0000Z 47.7N 14.8W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 26/1200Z...DISSIPATED

$$
Forecaster Zelinsky

>

2019-11-24 14:42


Original Message :

WTNT35 KNHC 241440
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 21
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Sun Nov 24 2019

...SEBASTIEN OR ITS REMNANTS FORECAST TO BRING GUSTY WINDS AND RAIN
TO PORTIONS OF THE AZORES LATER TODAY AND TONIGHT...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...37.4N 37.0W
ABOUT 550 MI...880 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 32 MPH...52 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the Azores should monitor the progress of Sebastien.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 37.4 North, longitude 37.0 West. Sebastien
is moving quickly toward the northeast near 32 mph (52 km/h). A
faster motion toward the northeast is expected during the next day
or so. On the forecast track, the center of Sebastien will pass
near the western Azores tonight.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. A slow decrease in the maximum winds is expected during the
next couple of days. Sebastien is forecast to become post-tropical
by early Monday, and it could degenerate into a trough of low
pressure at any time during the next couple of days. Regardless of
status, Sebastien or its remnants will likely continue to produce
tropical-storm-force winds for at least a couple more days.

Tropical-storm-force winds extend outward up to 115 miles (185 km)
from the center.

The estimated minimum central pressure is 994 mb (29.36 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: Sebastien or its remnants are expected to bring
gusty winds and rain to the Azores beginning later today and
tonight. Please see products issued by the Portuguese Institute for
the Sea and the Atmosphere (IPMA) for more information.

SURF: Swells generated by Sebastien are expected to reach the
Azores later today and tonight. These swells are likely to cause
life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Zelinsky

>

2019-11-24 14:42


Original Message :

WTNT25 KNHC 241439
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC SUN NOV 24 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE AZORES SHOULD MONITOR THE PROGRESS OF SEBASTIEN.

TROPICAL STORM CENTER LOCATED NEAR 37.4N 37.0W AT 24/1500Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 28 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 20NE 20SE 0SW 0NW.
34 KT....... 90NE 100SE 60SW 60NW.
12 FT SEAS.. 90NE 150SE 330SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 37.4N 37.0W AT 24/1500Z
AT 24/1200Z CENTER WAS LOCATED NEAR 36.5N 38.7W

FORECAST VALID 25/0000Z 39.8N 31.0W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 40SE 30SW 0NW.
34 KT... 90NE 140SE 120SW 70NW.

FORECAST VALID 25/1200Z 43.8N 22.0W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 40SE 40SW 0NW.
34 KT...110NE 190SE 190SW 70NW.

FORECAST VALID 26/0000Z 47.7N 14.8W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...140NE 250SE 200SW 80NW.

FORECAST VALID 26/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 37.4N 37.0W

NEXT ADVISORY AT 24/2100Z

$$
FORECASTER ZELINSKY

>

2019-11-24 08:49


Original Message :

WTNT45 KNHC 240847
TCDAT5

Tropical Storm Sebastien Discussion Number 20
NWS National Hurricane Center Miami FL AL202019
500 AM AST Sun Nov 24 2019

Sebastien is on the slow boat to becoming fully extratropical.
Just within the past few hours, the cyclone has taken on an
appearance more resembling a subtropical cyclone, with all of its
deep convection located in a band to the north of the center and it
being co-located with an upper-level shortwave trough. Based on
Sebastien's evolving structure, TAFB provided a subtropical
classification of ST3.5. Combining this estimate with the most
recent ADT and SATCON estimates, the initial intensity remains 55
kt.

Since Sebastien's extratropical transition has been so drawn out,
it's difficult to pinpoint exactly when the process will be
complete. Phase-space diagrams from the GFS and ECMWF models
indicate that the cyclone will be deep cold core within the next
6-12 hours. However, these models keep the low-level vortex
separate from a second upstream upper-level trough for the next 30
hours, and they also keep deep convection going (in simulated
satellite imagery) near but to the north of the center for that same
amount of time. Because of deep-layer shear around 40 kt and sea
surface temperatures near 20C, the official forecast continues to
show extratropical transition complete by 24 hours, but that
forecast should be considered with a margin of error of plus or
minus 12 hours. Regardless of its status, Sebastien is forecast to
only gradually lose strength over the next 48 hours and is likely to
bring gusty winds and heavy rains to portions of the Azores later
today and tonight. Please see products issued by the Portuguese
Institute for the Sea and the Atmosphere (IPMA) for more
information.

The northeastward acceleration continues, with Sebastian moving
050/29 kt. Additional acceleration is expected during the next 24
hours, with the new NHC track forecast a little faster than the
previous iteration and generally a blend of the TVCN and HCCA
consensus aids. No forecast points are provided starting at 72
hours since by that time Sebastien is expected to have merged with
another weather system southwest of Ireland and the United Kingdom.
This larger complex system could bring gusty winds and heavy rains
to portions of western Europe within the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0900Z 36.0N 40.0W 55 KT 65 MPH
12H 24/1800Z 38.5N 34.8W 55 KT 65 MPH
24H 25/0600Z 42.1N 26.2W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 25/1800Z 46.2N 17.5W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 26/0600Z 50.0N 11.4W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 27/0600Z...MERGED WITH ANOTHER WEATHER SYSTEM

$$
Forecaster Berg

>

2019-11-24 08:48


Original Message :

WTNT35 KNHC 240846
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 20
NWS National Hurricane Center Miami FL AL202019
500 AM AST Sun Nov 24 2019

...SEBASTIEN ACCELERATING NORTHEASTWARD TOWARD THE WESTERN AZORES...
...FORECAST TO BECOME POST-TROPICAL OVER THE NEXT DAY OR SO...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...36.0N 40.0W
ABOUT 730 MI...1175 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 50 DEGREES AT 33 MPH...54 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in the Azores should monitor the progress of Sebastien.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Storm Sebastien was
located near latitude 36.0 North, longitude 40.0 West. Sebastien is
moving faster toward the northeast near 33 mph (54 km/h), and an
additional increase in speed toward the northeast is expected
during the next day or so. On the forecast track, the center of
Sebastien will pass near the western Azores tonight.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. A slow decrease in the maximum winds is expected
during the next couple of days. Sebastien is forecast to become
post-tropical tonight and then merge with another weather system
over the northeastern Atlantic on Tuesday.

Tropical-storm-force winds extend outward up to 115 miles (185 km)
from the center.

The estimated minimum central pressure is 994 mb (29.36 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: Regardless of its status, Sebastien or its remnants
are expected to bring gusty winds and rain to the Azores beginning
later today. Please see products issued by the Portuguese Institute
for the Sea and the Atmosphere (IPMA) for more information.

SURF: Swells generated by Sebastien are expected to reach the
Azores later today and tonight. These swells are likely to cause
life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Berg

>

2019-11-24 08:48


Original Message :

WTNT25 KNHC 240846
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 20
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0900 UTC SUN NOV 24 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

INTERESTS IN THE AZORES SHOULD MONITOR THE PROGRESS OF SEBASTIEN.

TROPICAL STORM CENTER LOCATED NEAR 36.0N 40.0W AT 24/0900Z
POSITION ACCURATE WITHIN 45 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 50 DEGREES AT 29 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 20NE 20SE 0SW 0NW.
34 KT....... 90NE 100SE 60SW 60NW.
12 FT SEAS.. 90NE 150SE 330SW 90NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 36.0N 40.0W AT 24/0900Z
AT 24/0600Z CENTER WAS LOCATED NEAR 35.2N 41.7W

FORECAST VALID 24/1800Z 38.5N 34.8W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 40SE 30SW 0NW.
34 KT...100NE 140SE 100SW 60NW.

FORECAST VALID 25/0600Z 42.1N 26.2W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 50SE 40SW 0NW.
34 KT...110NE 170SE 170SW 60NW.

FORECAST VALID 25/1800Z 46.2N 17.5W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 200SE 180SW 60NW.

FORECAST VALID 26/0600Z 50.0N 11.4W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...130NE 240SE 240SW 60NW.

FORECAST VALID 27/0600Z...MERGED WITH ANOTHER WEATHER SYSTEM

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 36.0N 40.0W

NEXT ADVISORY AT 24/1500Z

$$
FORECASTER BERG

>

2019-11-24 03:59


Original Message :

WTNT82 EGRR 240359

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 0000UTC 24.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 33.6N 44.5W

ATCF IDENTIFIER : AL202019

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 24.11.2019 0 33.6N 44.5W 993 48
1200UTC 24.11.2019 12 36.5N 38.9W 991 46
0000UTC 25.11.2019 24 39.7N 30.9W 986 52
1200UTC 25.11.2019 36 43.9N 21.5W 977 50
0000UTC 26.11.2019 48 48.4N 13.8W 968 49
1200UTC 26.11.2019 60 50.9N 11.4W 958 47
0000UTC 27.11.2019 72 50.8N 8.2W 965 39
1200UTC 27.11.2019 84 50.7N 3.5W 974 41
0000UTC 28.11.2019 96 CEASED TRACKING


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

MET OFFICE, EXETER, UK

TOO 240358

>

2019-11-24 03:59


Original Message :

WTNT80 EGRR 240358

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 00UTC 24.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 33.6N 44.5W

ATCF IDENTIFIER : AL202019

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
00UTC 24.11.2019 33.6N 44.5W MODERATE
12UTC 24.11.2019 36.5N 38.9W MODERATE LITTLE CHANGE
00UTC 25.11.2019 39.7N 30.9W MODERATE INTENSIFYING SLIGHTLY
12UTC 25.11.2019 43.9N 21.5W STRONG INTENSIFYING SLIGHTLY
00UTC 26.11.2019 48.4N 13.8W STRONG INTENSIFYING SLIGHTLY
12UTC 26.11.2019 50.9N 11.4W INTENSE INTENSIFYING SLIGHTLY
00UTC 27.11.2019 50.8N 8.2W STRONG WEAKENING SLIGHTLY
12UTC 27.11.2019 50.7N 3.5W STRONG WEAKENING SLIGHTLY
00UTC 28.11.2019 BELOW TROPICAL STORM STRENGTH


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

BULLETINS ARE NOW AVAILABLE WHICH PROVIDE EXPLICIT GUIDANCE
ON CENTRAL PRESSURE AND MAXIMUM WIND SPEED.
FOR FURTHER INFORMATION CONTACT TROPICAL_CYCLONES@METOFFICE.GOV.UK

MET OFFICE, EXETER, UK

TOO 240358

>

2019-11-24 02:57


Original Message :

WTNT45 KNHC 240255
TCDAT5

Tropical Storm Sebastien Discussion Number 19
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Sat Nov 23 2019

Over the large scale, Sebastien appears to be undergoing
extratropical transition, with a large cirrus shield on the
northern side of the storm and unimpressive convection overall.
Near the center, however, the storm still has a small inner core,
with what appears to be a faint eye feature forming during the past
few hours in conventional satellite imagery. This feature also
shows up in recent microwave data, suggesting that Sebastien still
has more of its tropical character than a cursory look would
indicate. Thus, Sebastien is held as a tropical cyclone and, since
Dvorak and SATCON estimates remain at 55 kt, the initial wind speed
is held at that value. Unfortunately all 3 scatterometer satellites
missed the cyclone this evening.

Sebastien is quickly moving up on my list of most annoying storms
during the 2019 season, and hopefully this isn't another night of
it making my forecast look silly. I think (hope?) the intensity
outlook is getting easier since the storm will be moving over
sub-20C waters by tomorrow morning. There are no signs of
significant upper-level cooling at that time, so Sebastien will
probably be struggling to produce any organized deep convection.
Since baroclinic forcing also appears to be on the wane, a slow
weakening is anticipated, and a more complete extratropical
transition is forecast by this time tomorrow. This is also
indicated by cyclone phase space diagrams derived from the GFS and
ECMWF models. While I might have a little more confidence in this
prediction than a couple of days ago, I also wouldn't be surprised
if Sebastien had another trick up its sleeve.

The storm is accelerating northeastward, now estimated at
045/27 kt. The evening model guidance continues the trend noted
by my predecessor of a faster motion, so the new NHC prediction is
shifted in that direction, and somewhat to the north. Sebastien or
its extratropical remnants are expected to bring gusty winds and
rain to the Azores beginning on Sunday. Please see products issued
by the Portuguese Institute for the Sea and the Atmosphere (IPMA)
for more information.


FORECAST POSITIONS AND MAX WINDS

INIT 24/0300Z 34.4N 43.1W 55 KT 65 MPH
12H 24/1200Z 37.0N 38.7W 55 KT 65 MPH
24H 25/0000Z 40.1N 31.1W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 25/1200Z 43.9N 22.3W 50 KT 60 MPH...POST-TROP/EXTRATROP
48H 26/0000Z 48.0N 14.5W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 27/0000Z...DISSIPATED

$$
Forecaster Blake

>

2019-11-24 02:55


Original Message :

WTNT35 KNHC 240253
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 19
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Sat Nov 23 2019

...SEBASTIEN REFUSES TO WEAKEN AS IT RACES NORTHEASTWARD...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...34.4N 43.1W
ABOUT 930 MI...1495 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 45 DEGREES AT 31 MPH...50 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Sebastien
was located near latitude 34.4 North, longitude 43.1 West. Sebastien
is moving toward the northeast near 31 mph (50 km/h), and an even
faster motion in that general direction is expected during the next
day or two.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. A slow decrease in the maximum winds is expected
during the next couple of days. Sebastien is forecast to become
post-tropical late on Sunday and dissipate early next week.

Tropical-storm-force winds extend outward up to 90 miles (150 km)
from the center.

The estimated minimum central pressure is 994 mb (29.36 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: Regardless of its status, Sebastien or its remnants
are expected to bring gusty winds and rain to the Azores beginning
Sunday. Please see products issued by the Portuguese Institute for
the Sea and the Atmosphere (IPMA) for more information.

SURF: Swells generated by Sebastien are expected to reach the
Azores early next week. These swells are likely to cause
life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Blake

>

2019-11-24 02:54


Original Message :

WTNT25 KNHC 240252
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 19
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0300 UTC SUN NOV 24 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 34.4N 43.1W AT 24/0300Z
POSITION ACCURATE WITHIN 45 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 45 DEGREES AT 27 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 994 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 20NE 20SE 0SW 0NW.
34 KT....... 70NE 80SE 40SW 60NW.
12 FT SEAS..120NE 150SE 300SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 34.4N 43.1W AT 24/0300Z
AT 24/0000Z CENTER WAS LOCATED NEAR 33.5N 44.5W

FORECAST VALID 24/1200Z 37.0N 38.7W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 20NE 30SE 30SW 0NW.
34 KT...120NE 130SE 80SW 60NW.

FORECAST VALID 25/0000Z 40.1N 31.1W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 50SE 40SW 0NW.
34 KT...130NE 140SE 100SW 70NW.

FORECAST VALID 25/1200Z 43.9N 22.3W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 50SE 40SW 0NW.
34 KT...140NE 150SE 130SW 90NW.

FORECAST VALID 26/0000Z 48.0N 14.5W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...150NE 180SE 180SW 110NW.

FORECAST VALID 27/0000Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 34.4N 43.1W

NEXT ADVISORY AT 24/0900Z

$$
FORECASTER BLAKE

>

2019-11-23 20:40


Original Message :

WTNT45 KNHC 232038
TCDAT5

Tropical Storm Sebastien Discussion Number 18
NWS National Hurricane Center Miami FL AL202019
500 PM AST Sat Nov 23 2019

Sebastien's cloud pattern is beginning to resemble that of an
extratropical cyclone, with a shield of moderately cold cloud tops
extending well to the north of the cyclone's surface center. That
said, Sebastien is still producing enough convection near its center
to be considered a tropical cyclone for now. ASCAT-B data that
arrived shortly after the last advisory was issued had support for
55 kt and that is the basis for the initial intensity. The ASCAT
data also showed that the surface wind circulation of Sebastien is
elongated but still closed.

Sebastien is accelerating northeastward, with an initial motion of
045/26 kt. Most of the 12Z models show a significantly faster
northeastward track for the tropical storm and the official forecast
has been adjusted accordingly. However, the NHC forecast is slower
than the model consensus and additional large changes may be
required in the next advisory. Confidence in the track forecast
remains low due to the continued lack of run-to-run consistency
amongst the models. With regard to intensity, a majority of the
guidance calls for little change in strength since it seems that
baroclinic forcing will at least offset the negative influences of
decreasing SSTs and high shear during the next day or two. The NHC
intensity forecast is very near the consensus. Cyclone phase-space
diagrams derived from the GFS and ECMWF indicate that extratropical
transition could occur by Sunday afternoon, but the NHC forecast is
slightly more conservative. The reality is that Sebastien could
become extratropical or open into a trough at nearly any time
between this evening and early next week.

Sebastien or its remnants are expected to bring gusty winds and
rain to the Azores beginning on Sunday. Please see products issued
by the Portuguese Institute for the Sea and the Atmosphere (IPMA)
for more information.


FORECAST POSITIONS AND MAX WINDS

INIT 23/2100Z 32.4N 45.4W 55 KT 65 MPH
12H 24/0600Z 35.0N 41.5W 55 KT 65 MPH
24H 24/1800Z 37.8N 35.3W 55 KT 65 MPH
36H 25/0600Z 40.9N 27.6W 55 KT 65 MPH...POST-TROP/EXTRATROP
48H 25/1800Z 44.8N 19.3W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 26/1800Z...DISSIPATED

$$
Forecaster Zelinsky

>

2019-11-23 20:39


Original Message :

WTNT35 KNHC 232037
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 18
NWS National Hurricane Center Miami FL AL202019
500 PM AST Sat Nov 23 2019

...SEBASTIEN GALLOPING QUICKLY NORTHEASTWARD...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...32.4N 45.4W
ABOUT 1105 MI...1780 KM WSW OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 45 DEGREES AT 28 MPH...44 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Sebastien was
located near latitude 32.4 North, longitude 45.4 West. Sebastien is
moving quickly toward the northeast near 28 mph (44 km/h). A fast
northeastward motion is expected for the next couple of days.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. Little change in the maximum winds is expected during the
next couple of days. Sebastien is forecast to become post-tropical
on Sunday and dissipate early next week.

Tropical-storm-force winds extend outward up to 90 miles (150 km)
from the center.

The estimated minimum central pressure is 997 mb (29.44 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: Regardless of its status, Sebastien or its remnants
are expected to bring gusty winds and rain to the Azores beginning
Sunday. Please see products issued by the Portuguese Institute for
the Sea and the Atmosphere (IPMA) for more information.

SURF: Swells generated by Sebastien are expected to reach the
Azores early next week. These swells are likely to cause
life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Zelinsky

>

2019-11-23 20:39


Original Message :

WTNT25 KNHC 232037
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
2100 UTC SAT NOV 23 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 32.4N 45.4W AT 23/2100Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 45 DEGREES AT 24 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 997 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 20NE 20SE 0SW 0NW.
34 KT....... 70NE 80SE 40SW 60NW.
12 FT SEAS..120NE 120SE 150SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 32.4N 45.4W AT 23/2100Z
AT 23/1800Z CENTER WAS LOCATED NEAR 31.4N 46.4W

FORECAST VALID 24/0600Z 35.0N 41.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 20NE 30SE 20SW 0NW.
34 KT... 70NE 110SE 60SW 60NW.

FORECAST VALID 24/1800Z 37.8N 35.3W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 50SE 40SW 0NW.
34 KT... 80NE 140SE 100SW 70NW.

FORECAST VALID 25/0600Z 40.9N 27.6W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 60SE 40SW 0NW.
34 KT... 90NE 150SE 130SW 90NW.

FORECAST VALID 25/1800Z 44.8N 19.3W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 60SE 50SW 0NW.
34 KT...110NE 180SE 180SW 110NW.

FORECAST VALID 26/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 32.4N 45.4W

NEXT ADVISORY AT 24/0300Z

$$
FORECASTER ZELINSKY

>

2019-11-23 14:56


Original Message :

WTNT45 KNHC 231454
TCDAT5

Tropical Storm Sebastien Discussion Number 17
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Sat Nov 23 2019

First-light visible imagery and a few late-arriving microwave
overpasses revealed that Sebastien's elongated center is located
well northeast of previous estimates. It isn't clear if the center
reformed or if it simply accelerated more than expected overnight,
but the initial motion estimate is now 055/23 kt. A significant
change to the track forecast was made based on the updated
initial position, and the NHC forecast now shows a much faster
motion for Sebastien.

The cyclone's cloud pattern is somewhat ragged and does not look
entirely tropical. That said, Sebastien is still producing enough
deep convection to be classified as a tropical storm. Unfortunately,
no ASCAT data was available this morning to help assess the strength
of the winds or how well-defined the circulation is at the surface.
The initial intensity is conservatively maintained at 55 kt based
primarily on continuity from previous advisories, but this could be
generous since Dvorak intensity estimates are lower.

Every aspect of the forecast remains highly uncertain. The models
have been extremely inconsistent in forecasting Sebastien, with the
guidance varying drastically from run to run and with unusually
large spread in each forecast. The latest indications are that
Sebastien will move quickly northeastward with little change in
strength for the next few days before it eventually opens into a
trough around the time it nears the Azores in a couple of days.
Simulated satellite imagery suggests that the cyclone will still
produce enough deep convection to be classified as a tropical storm
through Sunday, though it could become post-tropical before it
reaches the Azores. Given the elongated nature of Sebastien's
circulation and its fast forward speed, it could also open into a
trough and dissipate at any time.

It is not currently clear if Sebastien will reach the Azores as a
tropical storm. Regardless of its status, Sebastien or its remnants
could bring gusty winds and rain to the Azores beginning Sunday.
Please see products issued by the Portuguese Institute for the Sea
and the Atmosphere (IPMA) for more information.


FORECAST POSITIONS AND MAX WINDS

INIT 23/1500Z 30.4N 47.7W 55 KT 65 MPH
12H 24/0000Z 32.1N 44.5W 55 KT 65 MPH
24H 24/1200Z 34.4N 40.0W 55 KT 65 MPH
36H 25/0000Z 36.8N 34.0W 55 KT 65 MPH
48H 25/1200Z 39.3N 26.7W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 26/1200Z...DISSIPATED

$$
Forecaster Zelinsky

>

2019-11-23 14:54


Original Message :

WTNT35 KNHC 231452
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 17
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Sat Nov 23 2019

...SEBASTIEN DISORGANIZED BUT APPEARS TO BE MAINTAINING STRENGTH...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...30.4N 47.7W
ABOUT 1290 MI...2075 KM WSW OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 26 MPH...43 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 30.4 North, longitude 47.7 West. Sebastien
is moving toward the northeast near 26 mph (43 km/h). A fast
northeastward or east-northeastward motion is expected during the
next day or two.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. Little change in the maximum wind speed is expected during
the next couple of days. Sebastien is forecast to become
post-tropical by Monday and it could become a remnant trough of low
pressure sooner than that.

Tropical-storm-force winds extend outward up to 115 miles (185 km)
from the center.

The estimated minimum central pressure is 997 mb (29.44 inches).


HAZARDS AFFECTING LAND
----------------------
WIND AND RAIN: Regardless of its status, Sebastien or its remnants
could bring gusty winds and rain to the Azores beginning Sunday.
Please see products issued by the Portuguese Institute for the Sea
and the Atmosphere (IPMA) for more information.

SURF: Swells generated by Sebastien are expected to reach the
Azores early next week. These swells are likely to cause
life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Zelinsky

>

2019-11-23 14:54


Original Message :

WTNT25 KNHC 231451
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC SAT NOV 23 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 30.4N 47.7W AT 23/1500Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 23 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 997 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 50NE 50SE 0SW 0NW.
34 KT.......100NE 100SE 80SW 80NW.
12 FT SEAS..120NE 120SE 150SW 180NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 30.4N 47.7W AT 23/1500Z
AT 23/1200Z CENTER WAS LOCATED NEAR 29.5N 48.5W

FORECAST VALID 24/0000Z 32.1N 44.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 40NE 50SE 0SW 0NW.
34 KT... 90NE 120SE 80SW 80NW.

FORECAST VALID 24/1200Z 34.4N 40.0W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 50SE 40SW 0NW.
34 KT... 80NE 140SE 100SW 80NW.

FORECAST VALID 25/0000Z 36.8N 34.0W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 60SE 50SW 0NW.
34 KT... 80NE 150SE 120SW 90NW.

FORECAST VALID 25/1200Z 39.3N 26.7W...POST-TROP/EXTRATROP
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 60SE 50SW 0NW.
34 KT... 80NE 170SE 170SW 130NW.

FORECAST VALID 26/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 30.4N 47.7W

NEXT ADVISORY AT 23/2100Z

$$
FORECASTER ZELINSKY

>

2019-11-23 12:33


Original Message :

WTNT65 KNHC 231231
TCUAT5

Tropical Storm Sebastien Tropical Cyclone Update
NWS National Hurricane Center Miami FL AL202019
830 AM AST Sat Nov 23 2019

...CENTER OF SEBASTIEN FARTHER NORTHEAST THAN PREVIOUSLY
ESTIMATED...

Recent microwave and visible satellite imagery indicate that the
center of Sebastien is moving faster than forecast and is now
located northeast of previous estimates. This will be reflected in
the next advisory issued by 11 AM AST (1500 UTC).


SUMMARY OF 830 AM AST...1230 UTC...INFORMATION
----------------------------------------------
LOCATION...29.5N 48.5W
ABOUT 1365 MI...2195 KM WSW OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 24 MPH...39 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

$$
Forecaster Zelinsky

>

2019-11-23 08:34


Original Message :

WTNT45 KNHC 230833
TCDAT5

Tropical Storm Sebastien Discussion Number 16
NWS National Hurricane Center Miami FL AL202019
500 AM AST Sat Nov 23 2019

The cloud pattern of Sebastien has changed significantly overnight.
Deep convection has decreased substantially during the past several
hours and the remaining thunderstorms are organized around a
mid-level eye feature seen in satellite images. Model vertical
cross sections indicate that Sebastien is extremely titled with the
low-level center, although I can't see it, likely well displaced to
the southwest of the mid-level eye. The initial intensity is held
at 55 kt based on the ASCAT data that came in a little after 00 Z,
but it looks like Sebastien is on a weakening trend.

Strong southwesterly vertically wind shear of about 40 kt is
responsible for the titled structure of the cyclone. Since the
shear is not expected to let up and because Sebastien is headed for
steadily cooler waters, it seems reasonable to assume that weakening
is likely. Although the models agree that Sebastien should slowly
lose its strength, it remains unclear if Sebastien will transition
to a post-tropical cyclone before it opens up into a trough during
the next few days. The NHC forecast continues to show dissipation
by day 3, but it is certainty possible that it dissipates before
then.

The tropical storm is moving east-northeastward at 15 kt ahead of a
cold front and trough. This motion with an increase in forward
speed is expected during the next few days as Sebastien becomes more
embedded in the faster mid-latitude flow. The models are in
relatively good agreement, and only small changes were made to the
previous NHC forecast.

The initial wind radii were modified based on the aforementioned
ASCAT passes, and the 12-ft sea radii were adjusted based on ship
and altimeter data.

FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 27.8N 50.6W 55 KT 65 MPH
12H 23/1800Z 29.4N 48.2W 50 KT 60 MPH
24H 24/0600Z 31.6N 44.2W 45 KT 50 MPH
36H 24/1800Z 34.0N 38.8W 40 KT 45 MPH
48H 25/0600Z 37.0N 31.6W 35 KT 40 MPH
72H 26/0600Z...DISSIPATED

$$
Forecaster Cangialosi

>

2019-11-23 08:34


Original Message :

WTNT35 KNHC 230832
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 16
NWS National Hurricane Center Miami FL AL202019
500 AM AST Sat Nov 23 2019

...SEBASTIEN HOLDING ITS STRENGTH FOR NOW...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...27.8N 50.6W
ABOUT 1535 MI...2465 KM WSW OF THE AZORES
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Storm Sebastien was
located near latitude 27.8 North, longitude 50.6 West. Sebastien is
moving toward the east-northeast near 17 mph (28 km/h), and this
motion with an increase in forward speed is expected during the next
couple of days.

Maximum sustained winds are near 65 mph (100 km/h) with higher
gusts. Gradual weakening is anticipated, and Sebastien is forecast
to dissipate early next week.

Tropical-storm-force winds extend outward up to 115 miles (185 km)
from the center.

The estimated minimum central pressure is 997 mb (29.44 inches).


HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Sebastien are expected to reach the
Azores early next week. These swells are likely to cause
life-threatening surf and rip current conditions.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Cangialosi

>

2019-11-23 08:34


Original Message :

WTNT25 KNHC 230832
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0900 UTC SAT NOV 23 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 27.8N 50.6W AT 23/0900Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR 60 DEGREES AT 15 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 997 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 50NE 50SE 0SW 0NW.
34 KT.......100NE 100SE 80SW 80NW.
12 FT SEAS..180NE 180SE 180SW 210NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 27.8N 50.6W AT 23/0900Z
AT 23/0600Z CENTER WAS LOCATED NEAR 27.3N 51.4W

FORECAST VALID 23/1800Z 29.4N 48.2W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 40NE 40SE 0SW 0NW.
34 KT... 90NE 100SE 70SW 70NW.

FORECAST VALID 24/0600Z 31.6N 44.2W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 80NE 120SE 70SW 50NW.

FORECAST VALID 24/1800Z 34.0N 38.8W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 80NE 130SE 90SW 50NW.

FORECAST VALID 25/0600Z 37.0N 31.6W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 0NE 150SE 120SW 0NW.

FORECAST VALID 26/0600Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 27.8N 50.6W

NEXT ADVISORY AT 23/1500Z

$$
FORECASTER CANGIALOSI

>

2019-11-23 03:57


Original Message :

WTNT82 EGRR 230356

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 0000UTC 23.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 26.6N 53.0W

ATCF IDENTIFIER : AL202019

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 23.11.2019 0 26.6N 53.0W 1001 39
1200UTC 23.11.2019 12 28.1N 50.4W 1002 35
0000UTC 24.11.2019 24 30.6N 46.4W 1004 38
1200UTC 24.11.2019 36 32.8N 42.1W 998 43
0000UTC 25.11.2019 48 34.7N 36.8W 995 53
1200UTC 25.11.2019 60 36.6N 30.5W 991 54
0000UTC 26.11.2019 72 37.2N 23.2W 998 47
1200UTC 26.11.2019 84 CEASED TRACKING


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

MET OFFICE, EXETER, UK

TOO 230356

>

2019-11-23 03:57


Original Message :

WTNT80 EGRR 230356

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 00UTC 23.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 26.6N 53.0W

ATCF IDENTIFIER : AL202019

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
00UTC 23.11.2019 26.6N 53.0W WEAK
12UTC 23.11.2019 28.1N 50.4W WEAK LITTLE CHANGE
00UTC 24.11.2019 30.6N 46.4W WEAK LITTLE CHANGE
12UTC 24.11.2019 32.8N 42.1W MODERATE INTENSIFYING SLIGHTLY
00UTC 25.11.2019 34.7N 36.8W MODERATE LITTLE CHANGE
12UTC 25.11.2019 36.6N 30.5W MODERATE INTENSIFYING SLIGHTLY
00UTC 26.11.2019 37.2N 23.2W MODERATE WEAKENING SLIGHTLY
12UTC 26.11.2019 BELOW TROPICAL STORM STRENGTH


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

BULLETINS ARE NOW AVAILABLE WHICH PROVIDE EXPLICIT GUIDANCE
ON CENTRAL PRESSURE AND MAXIMUM WIND SPEED.
FOR FURTHER INFORMATION CONTACT TROPICAL_CYCLONES@METOFFICE.GOV.UK

MET OFFICE, EXETER, UK

TOO 230356

>

2019-11-23 02:39


Original Message :

WTNT45 KNHC 230237
TCDAT5

Tropical Storm Sebastien Discussion Number 15
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Fri Nov 22 2019

There is not much that I can add that my predecessors have not
already addressed except to say that Sebastien does not know that
is November near Thanksgiving.

One interesting aspect tonight is that although the cloud pattern
has not change at all today with the low-level center on the
southern edge of the convection due to shear, and with the same
Dvorak numbers, ASCAT data that just arrived showed numerous vectors
of 50 kt and a few near 55 kt. On this basis, the initial intensity
has been adjusted upward to 55 kt in this advisory.

Sebastien has to weaken since is heading toward a hostile
environment of increasing shear and cooler waters. It might not do
it tonight, but the weakening process must begin within the next 24
hours or so. Both the GFS and the ECMWF open up the circulation
beyond 48 hours, and with the hostile environment ahead, the NHC
forecast calls for gradual weakening and dissipation in 3 days.

The cyclone is moving toward the northeast of 055 degrees at 13 kt.
Sebastien is embedded within the mid-latitude westerly flow, and the
cyclone has nowhere to go but to continue moving northeastward
with increasing forward speed. Models vary in speed, but on average
they all suggest acceleration.

FORECAST POSITIONS AND MAX WINDS

INIT 23/0300Z 27.0N 52.2W 55 KT 65 MPH
12H 23/1200Z 28.2N 50.2W 55 KT 65 MPH
24H 24/0000Z 30.5N 46.5W 45 KT 50 MPH
36H 24/1200Z 32.6N 42.5W 40 KT 45 MPH
48H 25/0000Z 35.5N 36.0W 35 KT 40 MPH
72H 26/0000Z...DISSIPATED

$$
Forecaster Avila

>

2019-11-23 02:39


Original Message :

WTNT35 KNHC 230236
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 15
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Fri Nov 22 2019

...TENACIOUS SEBASTIEN DOES NOT KNOW IS NOVEMBER AND REFUSES TO
WEAKEN...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...27.0N 52.2W
ABOUT 920 MI...1485 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Sebastien
was located near latitude 27.0 North, longitude 52.2 West. Sebastien
is moving toward the northeast near 15 mph (24 km/h), and this
motion with an increase in forward speed is expected to continue
during the next couple of days.

Satellite data indicate that the maximum sustained winds are near
65 mph (100 km/h) with higher gusts. Gradual weakening is
anticipated, and Sebastien is forecast to dissipate by early next
week.

Tropical-storm-force winds extend outward up to 195 miles (315 km)
from the center.

The estimated minimum central pressure is 998 mb (29.47 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Avila

>

2019-11-23 02:38


Original Message :

WTNT25 KNHC 230236
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0300 UTC SAT NOV 23 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 27.0N 52.2W AT 23/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 13 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 998 MB
MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT.
50 KT....... 0NE 30SE 30SW 0NW.
34 KT.......170NE 140SE 50SW 100NW.
12 FT SEAS..150NE 120SE 90SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 27.0N 52.2W AT 23/0300Z
AT 23/0000Z CENTER WAS LOCATED NEAR 26.6N 52.8W

FORECAST VALID 23/1200Z 28.2N 50.2W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 0NE 30SE 0SW 0NW.
34 KT...140NE 120SE 50SW 90NW.

FORECAST VALID 24/0000Z 30.5N 46.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 120SE 50SW 60NW.

FORECAST VALID 24/1200Z 32.6N 42.5W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...100NE 130SE 50SW 50NW.

FORECAST VALID 25/0000Z 35.5N 36.0W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 0NE 100SE 0SW 0NW.

FORECAST VALID 26/0000Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 27.0N 52.2W

NEXT ADVISORY AT 23/0900Z

$$
FORECASTER AVILA

>

2019-11-22 20:34


Original Message :

WTNT45 KNHC 222032
TCDAT5

Tropical Storm Sebastien Discussion Number 14
NWS National Hurricane Center Miami FL AL202019
500 PM AST Fri Nov 22 2019

Sebastien's structure has not changed since this morning. ASCAT data
that arrived just after the issuance of the previous advisory showed
that the system was producing winds slightly above 45 kt, a little
higher than the previous estimate. Since the structure of the
tropical storm has not changed since the time of the ASCAT, the
intensity has been set at 50 kt. It should be noted that this is
merely an adjustment of the intensity assessment and is not an
indication of strengthening.

The agreement between the intensity models is remarkably poor. In
just the first 24 h of the forecast, the solutions range from
dissipation (HMON), to hurricane-strength (HWRF), to steady-state
(most of the global models). Since the shear is high and SSTs ahead
of the cyclone will be fairly cold, the solution that makes the
most sense to me is that of the global and statistical-dynamical
models, which generally show slow weakening during the next couple
of days. Dissipation is still expected within 72 h.

The Jekyll and Hyde behavior of the models isn't limited to the
intensity forecast. While it seems clear that Sebastien will move
east-northeastward or northeastward along the southern end of a
frontal boundary during the next couple of days, the speed at which
it will move is very unclear. The deeper the cyclone remains, the
more influence strong upper-level southwesterly winds will have on
its track, and the faster it will likely move. The latest track
guidance unanimously shows a dramatically faster forward motion of
Sebastien. In fact, the consensus now shows a forward speed nearly
twice as fast as the previous NHC advisory. The official forecast
continues to chase the models but has not been moved nearly as far
as HCCA or TVCN. Confidence in the track forecast is quite low.

FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 26.2N 53.7W 50 KT 60 MPH
12H 23/0600Z 27.3N 51.8W 50 KT 60 MPH
24H 23/1800Z 28.9N 49.2W 45 KT 50 MPH
36H 24/0600Z 31.0N 45.8W 45 KT 50 MPH
48H 24/1800Z 33.1N 41.5W 40 KT 45 MPH
72H 25/1800Z...DISSIPATED

$$
Forecaster Zelinsky

>

2019-11-22 20:34


Original Message :

WTNT35 KNHC 222032
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 14
NWS National Hurricane Center Miami FL AL202019
500 PM AST Fri Nov 22 2019

...MORE OF THE SAME FROM SEBASTIEN OVER THE CENTRAL ATLANTIC...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...26.2N 53.7W
ABOUT 815 MI...1315 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...ENE OR 65 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Sebastien was
located near latitude 26.2 North, longitude 53.7 West. The tropical
storm is moving toward the east-northeast near 16 mph (26 km/h). A
general east-northeastward to northeastward motion is expected
through the weekend.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Gradual weakening is anticipated and Sebastien is forecast to
dissipate by early next week.

Tropical-storm-force winds extend outward up to 195 miles (315 km)
from the center.

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Zelinsky

>

2019-11-22 20:34


Original Message :

WTNT25 KNHC 222031
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
2100 UTC FRI NOV 22 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 26.2N 53.7W AT 22/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR 65 DEGREES AT 14 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 30SE 0SW 0NW.
34 KT.......170NE 140SE 50SW 100NW.
12 FT SEAS..180NE 150SE 90SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 26.2N 53.7W AT 22/2100Z
AT 22/1800Z CENTER WAS LOCATED NEAR 25.8N 54.4W

FORECAST VALID 23/0600Z 27.3N 51.8W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 30SE 0SW 0NW.
34 KT...140NE 120SE 50SW 90NW.

FORECAST VALID 23/1800Z 28.9N 49.2W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 120SE 50SW 60NW.

FORECAST VALID 24/0600Z 31.0N 45.8W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 100SE 50SW 50NW.

FORECAST VALID 24/1800Z 33.1N 41.5W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...100NE 100SE 50SW 50NW.

FORECAST VALID 25/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 26.2N 53.7W

NEXT ADVISORY AT 23/0300Z

$$
FORECASTER ZELINSKY

>

2019-11-22 14:59


Original Message :

WTNT25 KNHC 221456 CCA
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 13...CORRECTED
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC FRI NOV 22 2019

CORRECTED WIND GUSTS AT INITIAL TIME

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 25.2N 55.3W AT 22/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR 75 DEGREES AT 13 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1000 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT.......120NE 140SE 50SW 70NW.
12 FT SEAS..150NE 150SE 90SW 180NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 25.2N 55.3W AT 22/1500Z
AT 22/1200Z CENTER WAS LOCATED NEAR 24.8N 55.9W

FORECAST VALID 23/0000Z 25.8N 53.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 90SE 60SW 60NW.

FORECAST VALID 23/1200Z 27.0N 51.3W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 80NE 90SE 60SW 60NW.

FORECAST VALID 24/0000Z 28.2N 49.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 80NE 90SE 50SW 50NW.

FORECAST VALID 24/1200Z 29.3N 46.3W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 70NE 80SE 0SW 0NW.

FORECAST VALID 25/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 25.2N 55.3W

NEXT ADVISORY AT 22/2100Z

$$
FORECASTER ZELINSKY

>

2019-11-22 14:51


Original Message :

WTNT45 KNHC 221449
TCDAT5

Tropical Storm Sebastien Discussion Number 13
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Fri Nov 22 2019

Sebastien is strongly sheared with deep convection limited to the
northeast quadrant of the cyclone. The intensity has been set at 45
kt, based primarily on the latest TAFB Dvorak classification and
recent ADT fixes. A partial ASCAT overpass at 1239 UTC may not have
captured the strongest winds, but showed a peak value of only 40 kt.
Recent visible imagery and the ASCAT data also indicate that
Sebastien's circulation is not quite as well defined as it was
yesterday, perhaps due to its close proximity to a nearby frontal
boundary.

A significant change was made to the intensity forecast earlier
this morning, and the latest forecast is in line with that new
thinking. Strong shear is expected to prevent Sebastien from getting
better organized, so gradual weakening is anticipated. The HWRF
is once again a notable outlier, as the 06Z run stubbornly forecasts
Sebastien to become a hurricane. While not impossible, that scenario
appears unlikely and has been discounted. Aside from the HWRF, the
dynamical guidance otherwise dissipates Sebastien within about 3
days, and this is reflected in the official forecast. Given
Sebastien's shallow and disorganized structure, it is certainly
possible that its wind field may become poorly-defined and the
system could dissipate sooner than currently forecast.

The tropical storm continues to move at a slower pace and to the
right of previous forecasts. The initial motion estimate is 075/13
kt. The latest NHC track forecast is slower and to the right of the
previous advisory, closer to the global model consensus. The cyclone
is expected to continue generally northeastward or
east-northeastward near the southern end of an eastward-moving
frontal boundary through the weekend or as long as it remains a
tropical cyclone.


FORECAST POSITIONS AND MAX WINDS

INIT 22/1500Z 25.2N 55.3W 45 KT 50 MPH
12H 23/0000Z 25.8N 53.5W 45 KT 50 MPH
24H 23/1200Z 27.0N 51.3W 45 KT 50 MPH
36H 24/0000Z 28.2N 49.0W 40 KT 45 MPH
48H 24/1200Z 29.3N 46.3W 35 KT 40 MPH
72H 25/1200Z...DISSIPATED

$$
Forecaster Zelinsky

>

2019-11-22 14:49


Original Message :

WTNT35 KNHC 221447
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 13
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Fri Nov 22 2019

...POORLY ORGANIZED SEBASTIEN HEADING EAST-NORTHEAST OVER THE
CENTRAL ATLANTIC...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...25.2N 55.3W
ABOUT 695 MI...1120 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...ENE OR 75 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 25.2 North, longitude 55.3 West. Sebastien
is moving toward the east-northeast near 15 mph (24 km/h). An
east-northeastward or northeastward motion at a similar forward
speed is expected through the weekend.

Maximum sustained winds have decreased to near 50 mph (85 km/h)
with higher gusts. Continued gradual weakening is anticipated and
Sebastien is forecast to dissipate by early next week.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 1000 mb (29.53 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Zelinsky

>

2019-11-22 14:49


Original Message :

WTNT25 KNHC 221447
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC FRI NOV 22 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 25.2N 55.3W AT 22/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR 75 DEGREES AT 13 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1000 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 60 KT.
34 KT.......120NE 140SE 50SW 70NW.
12 FT SEAS..150NE 150SE 90SW 180NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 25.2N 55.3W AT 22/1500Z
AT 22/1200Z CENTER WAS LOCATED NEAR 24.8N 55.9W

FORECAST VALID 23/0000Z 25.8N 53.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 90SE 60SW 60NW.

FORECAST VALID 23/1200Z 27.0N 51.3W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 80NE 90SE 60SW 60NW.

FORECAST VALID 24/0000Z 28.2N 49.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 80NE 90SE 50SW 50NW.

FORECAST VALID 24/1200Z 29.3N 46.3W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 70NE 80SE 0SW 0NW.

FORECAST VALID 25/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 25.2N 55.3W

NEXT ADVISORY AT 22/2100Z

$$
FORECASTER ZELINSKY

>

2019-11-22 08:36


Original Message :

WTNT45 KNHC 220834
TCDAT5

Tropical Storm Sebastien Discussion Number 12
NWS National Hurricane Center Miami FL AL202019
500 AM AST Fri Nov 22 2019

Sebastien has become less organized this morning. Strong
southwesterly vertical wind shear of about 40 kt and dry air have
caused the low-level center of the storm to become exposed to the
southwest of the main area of deep convection. The initial
intensity remains 50 kt, based on the earlier ASCAT data, but this
is a little above the latest Dvorak estimates and could be generous.

The center of Sebastien has turned more to the right than expected,
with the initial motion estimated to be 065/13 kt. The models have
changed significantly this cycle, and now show a much slower forward
motion to the northeast during the next few days. This change
appears to be connected to a more vertically shallow system that
moves in the lower-level flow. The NHC track forecast has been
adjusted considerably slower and a little to the right of the
previous one, but it still is faster than nearly all of the
typically reliable models. Future adjustments will likely be made
if the model trend continues.

It no longer appears that Sebastien will strengthen. In fact, all
of the intensity guidance now suggests that the storm will gradually
weaken during the next few days as Sebastien remains in strong wind
shear conditions and moves over progressively cooler waters. In
addition, the model guidance has finally come into agreement that
Sebastien will not merge with the nearby cold front. Instead, the
cyclone is expected to move ahead of the weakening front and become
a non-convective post-tropical cyclone in about 2 days, or less,
when it moves over SSTs below 22 C. As mentioned in the previous
discussion, NHC and the models have had a challenging time figuring
out when Sebastien would lose its tropical characteristics, and we
have held the transition timing steady at 48 hours for a while.
Although there is still uncertainty, the models are in better
agreement in the timing of this transition. This intensity forecast
is a little lower than the previous one to come into better
agreement with the latest models.


FORECAST POSITIONS AND MAX WINDS

INIT 22/0900Z 24.8N 57.0W 50 KT 60 MPH
12H 22/1800Z 26.0N 54.3W 50 KT 60 MPH
24H 23/0600Z 27.2N 51.7W 45 KT 50 MPH
36H 23/1800Z 28.7N 49.1W 40 KT 45 MPH
48H 24/0600Z 30.0N 46.2W 35 KT 40 MPH...POST-TROPICAL
72H 25/0600Z 33.3N 38.4W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 26/0600Z...DISSIPATED

$$
Forecaster Cangialosi

>

2019-11-22 08:36


Original Message :

WTNT35 KNHC 220834
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 12
NWS National Hurricane Center Miami FL AL202019
500 AM AST Fri Nov 22 2019

...SEBASTIEN NO LONGER EXPECTED TO STRENGTHEN...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...24.8N 57.0W
ABOUT 600 MI...965 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...ENE OR 65 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Storm Sebastien was
located near latitude 24.8 North, longitude 57.0 West. Sebastien is
moving toward the east-northeast near 15 mph (24 km/h). An
east-northeast to northeast motion is expected during the next few
days.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Gradual weakening is expected, and Sebastien is forecast to become
a post-tropical cyclone this weekend.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Cangialosi

>

2019-11-22 08:35


Original Message :

WTNT25 KNHC 220833
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0900 UTC FRI NOV 22 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 24.8N 57.0W AT 22/0900Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE EAST-NORTHEAST OR 65 DEGREES AT 13 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 60SE 0SW 0NW.
34 KT.......120NE 140SE 50SW 70NW.
12 FT SEAS..180NE 150SE 120SW 150NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 24.8N 57.0W AT 22/0900Z
AT 22/0600Z CENTER WAS LOCATED NEAR 24.6N 57.3W

FORECAST VALID 22/1800Z 26.0N 54.3W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 60SE 0SW 0NW.
34 KT...110NE 130SE 60SW 70NW.

FORECAST VALID 23/0600Z 27.2N 51.7W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 110SE 60SW 60NW.

FORECAST VALID 23/1800Z 28.7N 49.1W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 90NE 110SE 60SW 60NW.

FORECAST VALID 24/0600Z 30.0N 46.2W...POST-TROPICAL
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 70NE 80SE 0SW 0NW.

FORECAST VALID 25/0600Z 33.3N 38.4W...POST-TROP/REMNT LOW
MAX WIND 25 KT...GUSTS 35 KT.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 26/0600Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.8N 57.0W

NEXT ADVISORY AT 22/1500Z

$$
FORECASTER CANGIALOSI

>

2019-11-22 02:49


Original Message :

WTNT45 KNHC 220247
TCDAT5

Tropical Storm Sebastien Discussion Number 11
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Thu Nov 21 2019

Sebastien continues to produce a central dense overcast and a large
band on the southeastern side of the circulation. Recent
scatterometer data indicate that the maximum winds are at least 45
kt and, since there has been little overall change in the satellite
presentation within the past several hours, the initial wind speed
will stay 50 kt.

Two notable changes have been made on this forecast. As
foreshadowed in the previous forecast, the models are no longer
rapidly accelerating the storm to the northeast ahead of a
mid-latitude trough. Instead, there is better agreement tonight on a
steadier motion to the northeast due to the trough in the short
term. Sebastien will then continue moving northeastward embedded in
the mid-latitude southwesterly flow over the weekend. The new
forecast is substantially slower than the last one, but is still on
the faster side of the guidance due to continuity concerns.

The second significant change is that Sebastien is no longer
expected to become a hurricane. The cyclone will soon be moving
over sub-26C waters with strong shear, and it seems unlikely to
intensify much in these conditions. Model intensity guidance
continues to decrease, and the NHC forecast follows that trend.
Weakening should start by the weekend over even cooler waters in a
high-shear environment, and these factors are forecast to cause
Sebastien to transition into a non-convective low or extratropical
cyclone in 36-48 h. Careful watchers of the forecast will note that
NHC has predicted extratropical transition at 48 h since Sebastien
was born over 48 h ago, and this timing has been pushed back
primarily due to the slower-than-expected motion. Thus, this timing
can't be considered a particularly confident prediction until the
track forecast becomes more consistent.


FORECAST POSITIONS AND MAX WINDS

INIT 22/0300Z 24.7N 57.8W 50 KT 60 MPH
12H 22/1200Z 26.0N 55.5W 55 KT 65 MPH
24H 23/0000Z 28.0N 51.7W 55 KT 65 MPH
36H 23/1200Z 30.3N 47.7W 45 KT 50 MPH
48H 24/0000Z 32.7N 43.4W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 25/0000Z 37.5N 34.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 26/0000Z...DISSIPATED

$$
Forecaster Blake

>

2019-11-22 02:47


Original Message :

WTNT35 KNHC 220245
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 11
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Thu Nov 21 2019

...SEBASTIEN MOVING FASTER WITH NO CHANGE IN INTENSITY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.7N 57.8W
ABOUT 565 MI...905 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Sebastien
was located near latitude 24.7 North, longitude 57.8 West. Sebastien
is moving toward the northeast near 18 mph (30 km/h), and this
motion is expected to continue with an increase in forward speed
during the next few days.

Maximum sustained winds remain near 60 mph (95 km/h) with higher
gusts. Little change in strength is forecast overnight, with
weakening beginning by the weekend.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Blake

>

2019-11-22 02:47


Original Message :

WTNT25 KNHC 220245
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0300 UTC FRI NOV 22 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 24.7N 57.8W AT 22/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 16 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 60SE 0SW 0NW.
34 KT.......120NE 140SE 50SW 70NW.
12 FT SEAS..150NE 120SE 90SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 24.7N 57.8W AT 22/0300Z
AT 22/0000Z CENTER WAS LOCATED NEAR 24.3N 58.6W

FORECAST VALID 22/1200Z 26.0N 55.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 60SE 20SW 20NW.
34 KT...120NE 140SE 60SW 70NW.

FORECAST VALID 23/0000Z 28.0N 51.7W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 60SE 20SW 20NW.
34 KT...100NE 140SE 60SW 60NW.

FORECAST VALID 23/1200Z 30.3N 47.7W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 140SE 60SW 60NW.

FORECAST VALID 24/0000Z 32.7N 43.4W...POST-TROP/EXTRATROP
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...100NE 150SE 120SW 50NW.

FORECAST VALID 25/0000Z 37.5N 34.0W...POST-TROP/EXTRATROP
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 90NE 120SE 90SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 26/0000Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.7N 57.8W

NEXT ADVISORY AT 22/0900Z

$$
FORECASTER BLAKE

>

2019-11-21 20:34


Original Message :

WTNT45 KNHC 212032
TCDAT5

Tropical Storm Sebastien Discussion Number 10
NWS National Hurricane Center Miami FL AL202019
500 PM AST Thu Nov 21 2019

Convection associated with Sebastien has become better organized
during the past several hours, as a band has formed near and over
the center in the eastern semicircle. Overall, the cloud pattern
remains elongated from north-to-south as the storm is interacting
with a cold front not far to its northwest. Scatterometer data
received just after the last advisory indicated 45-50 kt winds, and
based on this and current satellite intensity estimates the initial
intensity remains 50 kt.

The cyclone has turned northeastward with the initial motion now
050/8. Southwesterly mid-latitude flow should steer Sebastien or
its remnants quickly northeastward, and the guidance is in good
agreement on the direction of movement during the next several
days. However, there is a significant spread in the forward speed,
with the new ECMWF run being much slower than the other guidance.
The new track forecast will be only slightly slower than the
previous forecast, but adjustments to the forecast forward speed
may be necessary later.

Sebastien is in an apparently unfavorable environment for
development due to strong shear, decreasing sea surface temperatures
along the forecast track, and an expected extratropical transition
as it merges with the front. The intensity guidance is rather
divergent during the first 24 h, with the SHIPS and LGEM models
showing weakening while the dynamical guidance continues to forecast
strengthening despite the environment. After that time, all
guidance indicates that Sebastien should weaken. The intensity
forecast continues the trend of the previous forecast in showing
some strengthening during the first 24 h in agreement with the
dynamical models, followed by weakening and extratropical transition
by 48 h. Given how close the cold front is to the storm at this
time, it is possible that extratropical transition could occur
earlier than currently forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 21/2100Z 23.8N 59.7W 50 KT 60 MPH
12H 22/0600Z 25.5N 57.1W 60 KT 70 MPH
24H 22/1800Z 27.9N 53.2W 65 KT 75 MPH
36H 23/0600Z 30.6N 48.4W 55 KT 65 MPH
48H 23/1800Z 33.5N 43.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 24/1800Z 39.0N 31.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 25/1800Z...DISSIPATED

$$
Forecaster Beven

>

2019-11-21 20:34


Original Message :

WTNT35 KNHC 212031
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 10
NWS National Hurricane Center Miami FL AL202019
500 PM AST Thu Nov 21 2019

...SEBASTIEN NOW MOVING NORTHEASTWARD ACROSS THE CENTRAL ATLANTIC...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...23.8N 59.7W
ABOUT 445 MI...715 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NE OR 50 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Sebastien was
located near latitude 23.8 North, longitude 59.7 West. Sebastien is
moving toward the northeast near 9 mph (15 km/h), and this motion is
expected to continue with an increase in forward speed during the
next few days.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Some strengthening is expected during the next 24 hours, and
Sebastien could become a hurricane on Friday. A weakening trend is
expected to begin by late Friday, and the system is likely to become
an extratropical cyclone on Saturday.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 998 mb (29.47 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Beven

>

2019-11-21 20:34


Original Message :

WTNT25 KNHC 212031
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
2100 UTC THU NOV 21 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 23.8N 59.7W AT 21/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTHEAST OR 50 DEGREES AT 8 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 998 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 80SE 0SW 0NW.
34 KT.......100NE 140SE 0SW 0NW.
12 FT SEAS..180NE 180SE 60SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 23.8N 59.7W AT 21/2100Z
AT 21/1800Z CENTER WAS LOCATED NEAR 23.5N 60.1W

FORECAST VALID 22/0600Z 25.5N 57.1W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 80SE 20SW 20NW.
34 KT...100NE 140SE 60SW 60NW.

FORECAST VALID 22/1800Z 27.9N 53.2W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 90SW 90NW.

FORECAST VALID 23/0600Z 30.6N 48.4W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 40NE 50SE 40SW 30NW.
34 KT...100NE 160SE 120SW 60NW.

FORECAST VALID 23/1800Z 33.5N 43.0W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 180SE 140SW 50NW.

FORECAST VALID 24/1800Z 39.0N 31.0W...POST-TROP/EXTRATROP
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 150SE 120SW 30NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 25/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 23.8N 59.7W

NEXT ADVISORY AT 22/0300Z

$$
FORECASTER BEVEN

>

2019-11-21 15:58


Original Message :

WTNT82 EGRR 211557

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 1200UTC 21.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 22.9N 60.7W

ATCF IDENTIFIER : AL202019

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 21.11.2019 0 22.9N 60.7W 999 42
0000UTC 22.11.2019 12 24.5N 58.1W 981 70
1200UTC 22.11.2019 24 26.6N 55.1W 975 70
0000UTC 23.11.2019 36 29.2N 50.4W 968 81
1200UTC 23.11.2019 48 32.0N 45.6W 970 75
0000UTC 24.11.2019 60 35.5N 40.4W 971 68
1200UTC 24.11.2019 72 38.4N 33.8W 975 65
0000UTC 25.11.2019 84 41.2N 25.2W 980 60
1200UTC 25.11.2019 96 44.4N 15.4W 982 54
0000UTC 26.11.2019 108 47.0N 4.7W 986 51
1200UTC 26.11.2019 120 CEASED TRACKING


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

MET OFFICE, EXETER, UK

TOO 211557

>

2019-11-21 15:58


Original Message :

WTNT80 EGRR 211557

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 12UTC 21.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 22.9N 60.7W

ATCF IDENTIFIER : AL202019

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 21.11.2019 22.9N 60.7W MODERATE
00UTC 22.11.2019 24.5N 58.1W MODERATE INTENSIFYING RAPIDLY
12UTC 22.11.2019 26.6N 55.1W STRONG INTENSIFYING SLIGHTLY
00UTC 23.11.2019 29.2N 50.4W STRONG INTENSIFYING SLIGHTLY
12UTC 23.11.2019 32.0N 45.6W STRONG LITTLE CHANGE
00UTC 24.11.2019 35.5N 40.4W STRONG LITTLE CHANGE
12UTC 24.11.2019 38.4N 33.8W STRONG WEAKENING SLIGHTLY
00UTC 25.11.2019 41.2N 25.2W STRONG WEAKENING SLIGHTLY
12UTC 25.11.2019 44.4N 15.4W MODERATE LITTLE CHANGE
00UTC 26.11.2019 47.0N 4.7W MODERATE WEAKENING SLIGHTLY
12UTC 26.11.2019 BELOW TROPICAL STORM STRENGTH


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

BULLETINS ARE NOW AVAILABLE WHICH PROVIDE EXPLICIT GUIDANCE
ON CENTRAL PRESSURE AND MAXIMUM WIND SPEED.
FOR FURTHER INFORMATION CONTACT TROPICAL_CYCLONES@METOFFICE.GOV.UK

MET OFFICE, EXETER, UK

TOO 211557

>

2019-11-21 14:51


Original Message :

WTNT45 KNHC 211449
TCDAT5

Tropical Storm Sebastien Discussion Number 9
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Thu Nov 21 2019

Sebastien continues to produce a large area of deep convection over
the eastern semicircle of the circulation, but the banding features
are not very well defined. The intensity estimate remains at 50 kt
based on a blend of subjective Dvorak estimates from TAFB and SAB.
A diffluent upper-level wind environment and warm waters are
expected to bring about some strengthening through tonight, however
the window of opportunity for strengthening will probably close
tomorrow morning. After that time, drier air and strong shear
should cause gradual weakening. The official intensity forecast is
a little above the model consensus. In a couple of days, the
GFS shows Sebastien becoming embedded in a frontal zone, signifying
the transition to an extratropical cyclone as shown in the NHC
forecast. The ECMWF model suggests that this event could occur
later, but the current close proximity of a front to Sebastian
argues for extratropical transition to occur within 48 hours.

The circulation is a bit elongated from south to north, and the
center remains difficult to locate. This results in a greater than
normal uncertainty in the initial motion, and my best guess is 030/7
kt. A turn toward the northeast, with acceleration, is expected
during the next couple of days due to the influence of a mid-level
trough. There is considerable along-track model spread, with the
ECMWF forecast being much slower than the majority of the guidance.
The official forecast is somewhat slower than the dynamical model
consensus out of respect for that typically reliable model.


FORECAST POSITIONS AND MAX WINDS

INIT 21/1500Z 23.5N 60.5W 50 KT 60 MPH
12H 22/0000Z 25.0N 58.3W 65 KT 75 MPH
24H 22/1200Z 27.2N 55.0W 70 KT 80 MPH
36H 23/0000Z 30.0N 50.4W 65 KT 75 MPH
48H 23/1200Z 33.2N 45.2W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 24/1200Z 39.7N 31.5W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 25/1200Z...DISSIPATED

$$
Forecaster Pasch

>

2019-11-21 14:50


Original Message :

WTNT35 KNHC 211448
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 9
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Thu Nov 21 2019

...SEBASTIEN EXPECTED TO BECOME A HURRICANE BY TONIGHT...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.5N 60.5W
ABOUT 405 MI...650 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NNE OR 30 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 23.5 North, longitude 60.5 West. Sebastien
is moving toward the north-northeast near 8 mph (13 km/h). A faster
northeastward motion is expected during the next few days.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Sebastien is forecast to become a hurricane by tonight, but a
weakening trend is expected to begin by late Friday. The system is
likely to become an extratropical cyclone by Saturday.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Pasch

>

2019-11-21 14:50


Original Message :

WTNT25 KNHC 211448
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC THU NOV 21 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 23.5N 60.5W AT 21/1500Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHEAST OR 30 DEGREES AT 7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 80SE 0SW 0NW.
34 KT.......100NE 140SE 0SW 0NW.
12 FT SEAS..210NE 150SE 60SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 23.5N 60.5W AT 21/1500Z
AT 21/1200Z CENTER WAS LOCATED NEAR 23.1N 60.8W

FORECAST VALID 22/0000Z 25.0N 58.3W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 30NE 80SE 20SW 20NW.
34 KT...100NE 140SE 60SW 60NW.

FORECAST VALID 22/1200Z 27.2N 55.0W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 90SW 90NW.

FORECAST VALID 23/0000Z 30.0N 50.4W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 50SE 40SW 30NW.
34 KT...100NE 140SE 100SW 80NW.

FORECAST VALID 23/1200Z 33.2N 45.2W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 50SE 30SW 30NW.
34 KT...100NE 160SE 120SW 60NW.

FORECAST VALID 24/1200Z 39.7N 31.5W...POST-TROP/EXTRATROP
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 150SE 120SW 30NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 25/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 23.5N 60.5W

NEXT ADVISORY AT 21/2100Z

$$
FORECASTER PASCH

>

2019-11-21 08:33


Original Message :

WTNT45 KNHC 210831
TCDAT5

Tropical Storm Sebastien Discussion Number 8
NWS National Hurricane Center Miami FL AL202019
500 AM AST Thu Nov 21 2019

Sebastien continues to produce a large area of showers and
thunderstorms over its southeastern quadrant with more disorganized
convection to the north and west of the center. Despite the fair
amount of convection, the cloud pattern lacks banding features and
the center of the storm has been challenging to locate. The
initial intensity is held at 50 kt based on ASCAT data from several
hours ago. This data also indicate that Sebastien's wind field is
quite lopsided, with all of its tropical-storm-force winds confined
to the eastern side of the circulation.

The initial motion of the storm is tough to assess given that there
is more than the usual amount of uncertainty in the current
position, but my best guess is 015/7 kt. A deep-layer trough over
the western Atlantic is approaching Sebastien, and that feature
should cause the storm to accelerate to the northeast during the
next few days. Although the models agree on the overall scenario,
there are major along-track or speed differences among the models,
with the GFS/HWRF/HMON being the fastest solutions and the ECMWF
being the slowest. In fact, at 48 hours, the spread between the GFS
and ECMWF models is more than 700 n mi. The NHC forecast lies
roughly near the middle of the guidance envelope and ends up near
the UKMET model, but this prediction is of low confidence.

Upper-level diffluence, relatively warm SSTs, and a moist
environment should allow for Sebastien to strengthen during the next
24 hours or so. In fact, all of the hurricane regional models show
significant or even rapid intensification during that time period.
Given the asymmetric structure of Sebastien currently, rapid
intensification seems unlikely, and the NHC intensity prediction
lies closer to the lower end of the guidance in the short term.
Beyond 24 hours, Sebastien will be moving into progressively more
hostile conditions of increasing shear, drier air, and cooler
waters. These conditions should end the opportunity for
strengthening and begin the process of extratropical transition.
Sebastien is expected to become fully extratropical in about 48
hours, but this could occur sooner if the GFS is correct or later if
the ECMWF is correct. The extratropical low is forecast to slowly
weaken and dissipate in about 4 days.

FORECAST POSITIONS AND MAX WINDS

INIT 21/0900Z 23.0N 61.2W 50 KT 60 MPH
12H 21/1800Z 24.5N 59.3W 60 KT 70 MPH
24H 22/0600Z 26.6N 56.4W 70 KT 80 MPH
36H 22/1800Z 29.4N 52.0W 70 KT 80 MPH
48H 23/0600Z 32.4N 47.1W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 24/0600Z 38.6N 34.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
96H 25/0600Z...DISSIPATED

$$
Forecaster Cangialosi

>

2019-11-21 08:33


Original Message :

WTNT35 KNHC 210831
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 8
NWS National Hurricane Center Miami FL AL202019
500 AM AST Thu Nov 21 2019

...SEBASTIEN FORECAST TO STRENGTHEN OVER THE CENTRAL ATLANTIC...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...23.0N 61.2W
ABOUT 355 MI...570 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Storm Sebastien was
located near latitude 23.0 North, longitude 61.2 West. Sebastien is
moving toward the north-northeast near 8 mph (13 km/h). A faster
northeastward motion is expected during the next few days.

Maximum sustained winds are near 60 mph (95 km/h) with higher gusts.
Gradual strengthening is forecast, and Sebastien could become a
hurricane tonight or Friday before weakening this weekend.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
east of the center.

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Cangialosi

>

2019-11-21 08:33


Original Message :

WTNT25 KNHC 210831
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0900 UTC THU NOV 21 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 23.0N 61.2W AT 21/0900Z
POSITION ACCURATE WITHIN 60 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHEAST OR 15 DEGREES AT 7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 80SE 0SW 0NW.
34 KT.......100NE 140SE 0SW 0NW.
12 FT SEAS..180NE 120SE 30SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 23.0N 61.2W AT 21/0900Z
AT 21/0600Z CENTER WAS LOCATED NEAR 22.7N 61.4W

FORECAST VALID 21/1800Z 24.5N 59.3W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 80SE 20SW 20NW.
34 KT...100NE 140SE 60SW 60NW.

FORECAST VALID 22/0600Z 26.6N 56.4W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 90SW 90NW.

FORECAST VALID 22/1800Z 29.4N 52.0W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 50SE 40SW 30NW.
34 KT...100NE 140SE 100SW 80NW.

FORECAST VALID 23/0600Z 32.4N 47.1W...POST-TROP/EXTRATROP
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 50SE 30SW 30NW.
34 KT...100NE 160SE 120SW 60NW.

FORECAST VALID 24/0600Z 38.6N 34.0W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 60NE 150SE 120SW 30NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 25/0600Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 23.0N 61.2W

NEXT ADVISORY AT 21/1500Z

$$
FORECASTER CANGIALOSI

>

2019-11-21 03:58


Original Message :

WTNT82 EGRR 210357

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 0000UTC 21.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 21.8N 62.0W

ATCF IDENTIFIER : AL202019

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 21.11.2019 0 21.8N 62.0W 1005 34
1200UTC 21.11.2019 12 22.8N 60.5W 999 42
0000UTC 22.11.2019 24 24.6N 57.9W 976 76
1200UTC 22.11.2019 36 27.0N 54.7W 975 67
0000UTC 23.11.2019 48 29.8N 50.0W 971 71
1200UTC 23.11.2019 60 32.5N 45.1W 979 73
0000UTC 24.11.2019 72 35.6N 39.6W 977 65
1200UTC 24.11.2019 84 38.3N 32.5W 979 62
0000UTC 25.11.2019 96 40.8N 24.0W 982 56
1200UTC 25.11.2019 108 43.3N 14.5W 989 50
0000UTC 26.11.2019 120 46.3N 4.4W 990 48
1200UTC 26.11.2019 132 CEASED TRACKING


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

MET OFFICE, EXETER, UK

TOO 210356

>

2019-11-21 02:56


Original Message :

WTNT45 KNHC 210253
TCDAT5

Tropical Storm Sebastien Discussion Number 7
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Wed Nov 20 2019

Deep convection has intensified near and to the southeast of the
center of Sebastien this evening, and a recent partial ASCAT
pass suggests the center is still on the edge of the thunderstorms.
Satellite intensity estimates have risen slightly, so the initial
wind speed is set to 50 kt, on the high side of the recent values.

The storm continues to move slowly to the north tonight.
Increasing deep-layer flow ahead of a mid-latitude trough should
turn Sebastien northeastward overnight and cause the cyclone to
further accelerate by late Thursday and Friday. The models aren't
in great agreement on how quickly the storm will move to the
northeast, however, with the model guidance having a stronger storm
generally moving faster to the northeast. Since Sebastien
isn't expected to get that intense, it makes physical sense to
avoid the fastest solutions. Thus, the new forecast is slower than
the last one, closer to the model consensus than the GFS-based
guidance.

The environment is forecast to become more conducive for
strengthening during the next 24 hours as significant upper-level
divergence increases near Sebastien. Combined with low or
moderate shear and warm waters, these conditions should support
further intensification, and the new NHC forecast now shows
Sebastien as a hurricane for a short period of time. Notably, this
forecast is still on the conservative side of the guidance, with all
of the regional hurricane models showing Sebastien becoming a fairly
potent hurricane in a day or two. This doesn't seem likely after
examining the model initial structure of the HWRF/HMON models, which
show a much more vertically aligned cyclone than Sebastien appears
to be now, so the NHC forecast is only a bit higher than the last
one. In a couple of days, the storm will be moving over cooler
waters, with increasing shear and baroclinicity. That should
facilitate Sebastien's transition to a non-tropical cyclone by the
end of the work week, but note that the extratropical transition
has been shifted back about a day due to the stronger-than-forecast
cyclone likely staying a little more separate from an incoming cold
front.


FORECAST POSITIONS AND MAX WINDS

INIT 21/0300Z 22.2N 61.5W 50 KT 60 MPH
12H 21/1200Z 23.3N 60.5W 55 KT 65 MPH
24H 22/0000Z 25.5N 57.7W 65 KT 75 MPH
36H 22/1200Z 28.0N 53.9W 65 KT 75 MPH
48H 23/0000Z 31.0N 49.0W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 24/0000Z 37.0N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
96H 25/0000Z...DISSIPATED

$$
Forecaster Blake

>

2019-11-21 02:54


Original Message :

WTNT35 KNHC 210252
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 7
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Wed Nov 20 2019

...SEBASTIEN COULD BECOME A HURRICANE ON THURSDAY OR FRIDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.2N 61.5W
ABOUT 295 MI...475 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Sebastien
was located near latitude 22.2 North, longitude 61.5 West. Sebastien
is moving toward the north near 7 mph (11 km/h). A turn to the
northeast is forecast overnight, with an increase in forecast speed
during the day on Thursday and Friday.

Maximum sustained winds have increased to near 60 mph (95 km/h) with
higher gusts. Some strengthening is forecast, and Sebastien could
become a hurricane late Thursday or Friday before weakening this
weekend.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Blake

>

2019-11-21 02:53


Original Message :

WTNT25 KNHC 210251
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0300 UTC THU NOV 21 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 22.2N 61.5W AT 21/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTH OR 10 DEGREES AT 6 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 999 MB
MAX SUSTAINED WINDS 50 KT WITH GUSTS TO 60 KT.
50 KT....... 0NE 40SE 0SW 0NW.
34 KT.......100NE 140SE 0SW 0NW.
12 FT SEAS..210NE 150SE 30SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 22.2N 61.5W AT 21/0300Z
AT 21/0000Z CENTER WAS LOCATED NEAR 21.9N 61.5W

FORECAST VALID 21/1200Z 23.3N 60.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 20NE 40SE 0SW 0NW.
34 KT...100NE 140SE 60SW 60NW.

FORECAST VALID 22/0000Z 25.5N 57.7W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 70SW 70NW.

FORECAST VALID 22/1200Z 28.0N 53.9W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 0NE 30SE 0SW 0NW.
50 KT... 40NE 60SE 40SW 30NW.
34 KT...100NE 140SE 90SW 80NW.

FORECAST VALID 23/0000Z 31.0N 49.0W...POST-TROP/EXTRATROP
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 30NE 50SE 30SW 30NW.
34 KT...100NE 140SE 90SW 70NW.

FORECAST VALID 24/0000Z 37.0N 38.0W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 60NE 150SE 120SW 30NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 25/0000Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 22.2N 61.5W

NEXT ADVISORY AT 21/0900Z

$$
FORECASTER BLAKE

>

2019-11-20 20:39


Original Message :

WTNT45 KNHC 202037
TCDAT5

Tropical Storm Sebastien Discussion Number 6
NWS National Hurricane Center Miami FL AL202019
500 PM AST Wed Nov 20 2019

Sebastien has changed little in organization today, with
northwesterly shear displacing the deep convection to the southeast
of an exposed low-level center. An ASCAT-C overpass late this
morning sampled peak winds of 41 kt, and so the initial advisory
intensity will remain 45 kt due to the assumption of undersampling
by the scatterometer.

Sebastien made its anticipated turn to the north earlier today, and
the current motion is now 360/05 kt. The cyclone should turn to the
northeast tonight and begin to accelerate as it gets embedded in
increasing southwesterly flow ahead of an approaching cold front and
associated mid- to upper- level trough. The official forecast track
is near the previous one through 24 hours, and a little slower and
to the south of it beyond that time due to a shift in the model
guidance.

The approaching trough should provide a diffluent environment aloft
over Sebastien beginning tonight and persisting until the system
makes the transition to an extratropical cyclone in a couple of
days. This is expected to result in some intensification over the
next day or so. Once extratropical, the cyclone should gradually
become absorbed into a frontal zone through the end of the week. The
official forecast is changed little from the previous one, and is
near the IVCN consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 20/2100Z 21.7N 61.5W 45 KT 50 MPH
12H 21/0600Z 22.7N 61.0W 50 KT 60 MPH
24H 21/1800Z 24.5N 59.0W 60 KT 70 MPH
36H 22/0600Z 27.2N 55.5W 60 KT 70 MPH
48H 22/1800Z 30.0N 51.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 23/1800Z...DISSIPATED

$$
Forecaster Latto

>

2019-11-20 20:38


Original Message :

WTNT35 KNHC 202036
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 6
NWS National Hurricane Center Miami FL AL202019
500 PM AST Wed Nov 20 2019

...SEBASTIEN MAKES ITS NORTHWARD TURN...
...EXPECTED TO BEGIN INTENSIFYING SOON...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...21.7N 61.5W
ABOUT 265 MI...425 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Sebastien was
located near latitude 21.7 North, longitude 61.5 West. Sebastien is
moving toward the north near 6 mph (9 km/h). A turn to the northeast
with an increase in forward speed is expected tonight and Thursday.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours. Sebastien
is expected to become an extratropical cyclone in a couple of days
and be absorbed by a cold front on Friday.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 1002 mb (29.59 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Latto

>

2019-11-20 20:37


Original Message :

WTNT25 KNHC 202035
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
2100 UTC WED NOV 20 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 21.7N 61.5W AT 20/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTH OR 360 DEGREES AT 5 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT.......100NE 140SE 0SW 70NW.
12 FT SEAS..240NE 150SE 0SW 120NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 21.7N 61.5W AT 20/2100Z
AT 20/1800Z CENTER WAS LOCATED NEAR 21.3N 61.7W

FORECAST VALID 21/0600Z 22.7N 61.0W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 20NE 20SE 0SW 0NW.
34 KT...100NE 140SE 0SW 70NW.

FORECAST VALID 21/1800Z 24.5N 59.0W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 50SE 0SW 30NW.
34 KT...100NE 140SE 0SW 70NW.

FORECAST VALID 22/0600Z 27.2N 55.5W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 70SW 70NW.

FORECAST VALID 22/1800Z 30.0N 51.4W...POST-TROP/EXTRATROP
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 90SW 70NW.

FORECAST VALID 23/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.7N 61.5W

NEXT ADVISORY AT 21/0300Z

$$
FORECASTER LATTO

>

2019-11-20 15:59


Original Message :

WTNT82 EGRR 201558

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC AND ATLANTIC

GLOBAL MODEL DATA TIME 1200UTC 20.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 20.8N 61.5W

ATCF IDENTIFIER : AL202019

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 20.11.2019 0 20.8N 61.5W 1007 37
0000UTC 21.11.2019 12 21.6N 61.5W 1004 37
1200UTC 21.11.2019 24 22.7N 60.5W 999 47
0000UTC 22.11.2019 36 24.3N 57.9W 983 68
1200UTC 22.11.2019 48 26.0N 55.0W 984 60
0000UTC 23.11.2019 60 27.5N 51.4W 990 56
1200UTC 23.11.2019 72 30.0N 47.6W 990 65
0000UTC 24.11.2019 84 32.8N 43.6W 998 48
1200UTC 24.11.2019 96 35.6N 38.0W 983 60
0000UTC 25.11.2019 108 38.0N 31.0W 979 61
1200UTC 25.11.2019 120 41.0N 22.3W 970 72
0000UTC 26.11.2019 132 44.2N 13.0W 963 63
1200UTC 26.11.2019 144 47.2N 6.6W 961 53


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

MET OFFICE, EXETER, UK

TOO 201558

>

2019-11-20 15:59


Original Message :

WTNT80 EGRR 201558

MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 12UTC 20.11.2019

TROPICAL STORM SEBASTIEN ANALYSED POSITION : 20.8N 61.5W

ATCF IDENTIFIER : AL202019

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
12UTC 20.11.2019 20.8N 61.5W WEAK
00UTC 21.11.2019 21.6N 61.5W WEAK LITTLE CHANGE
12UTC 21.11.2019 22.7N 60.5W MODERATE INTENSIFYING SLIGHTLY
00UTC 22.11.2019 24.3N 57.9W MODERATE INTENSIFYING RAPIDLY
12UTC 22.11.2019 26.0N 55.0W MODERATE LITTLE CHANGE
00UTC 23.11.2019 27.5N 51.4W MODERATE WEAKENING SLIGHTLY
12UTC 23.11.2019 30.0N 47.6W MODERATE LITTLE CHANGE
00UTC 24.11.2019 32.8N 43.6W MODERATE WEAKENING SLIGHTLY
12UTC 24.11.2019 35.6N 38.0W MODERATE INTENSIFYING RAPIDLY
00UTC 25.11.2019 38.0N 31.0W STRONG LITTLE CHANGE
12UTC 25.11.2019 41.0N 22.3W STRONG INTENSIFYING SLIGHTLY
00UTC 26.11.2019 44.2N 13.0W STRONG INTENSIFYING SLIGHTLY
12UTC 26.11.2019 47.2N 6.6W STRONG LITTLE CHANGE


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT.

BULLETINS ARE NOW AVAILABLE WHICH PROVIDE EXPLICIT GUIDANCE
ON CENTRAL PRESSURE AND MAXIMUM WIND SPEED.
FOR FURTHER INFORMATION CONTACT TROPICAL_CYCLONES@METOFFICE.GOV.UK

MET OFFICE, EXETER, UK

TOO 201558

>

2019-11-20 14:49


Original Message :

WTNT45 KNHC 201447
TCDAT5

Tropical Storm Sebastien Discussion Number 5
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Wed Nov 20 2019

Sebastien continues to struggle with dry air and northwesterly
shear, with satellite imagery showing an exposed low-level
center to the west of the deep convection. The current structure of
the storm should prevent significant intensification during the next
12 hours. After that time, Sebastien will begin to interact with a
mid- to upper-level trough that will produce upper-level divergence
over the cyclone. This will provide a window for Sebastien to
intensify before making the transition to an extratropical cyclone
in about 48 hours. All available guidance intensifies the storm, and
the dynamical models continue to strengthen it more than the
statistical models. In fact, the mesoscale models unanimously make
Sebastian a hurricane within 36 hours. However, these models are
likely intensifying the cyclone too quickly over the next 12 hours,
and therefore may have a slight high bias. The official forecast
takes this into account and keeps the storm just below hurricane
strength before extratropical transition by 48 hours, which is a
blend of the ECMWF and GFS solutions.

Sebastien appears to be approaching its westernmost point and a turn
to the north should begin later today, followed by acceleration to
the northeast starting tonight due to the influence of the
approaching trough. The track guidance is in agreement on this
overall scenario. The NHC forecast track is just slightly slower
than the previous one in the first 24 hours, and is close to the
model consensus.


FORECAST POSITIONS AND MAX WINDS

INIT 20/1500Z 21.1N 61.7W 45 KT 50 MPH
12H 21/0000Z 22.0N 61.7W 45 KT 50 MPH
24H 21/1200Z 23.7N 60.2W 55 KT 65 MPH
36H 22/0000Z 26.3N 57.2W 60 KT 70 MPH
48H 22/1200Z 29.8N 52.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 23/1200Z...DISSIPATED

$$
Forecaster Latto/Mello

>

2019-11-20 14:46


Original Message :

WTNT35 KNHC 201444
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 5
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Wed Nov 20 2019

...SEBASTIEN MAINTAINS INTENSITY...
...EXPECTED TO TURN NORTH SOON...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.1N 61.7W
ABOUT 220 MI...355 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 21.1 North, longitude 61.7 West. Sebastien
is moving toward the west near 7 mph (11 km/h). A turn to the north
is expected later today. A turn to the northeast with an increase
in forward speed is expected tonight and Thursday.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours. Sebastien
is expected to become an extratropical cyclone in a couple of days
and be absorbed by a cold front on Friday.

Tropical-storm-force winds extend outward up to 160 miles (260 km)
from the center.

The estimated minimum central pressure is 1002 mb (29.59 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Latto/Mello

>

2019-11-20 14:46


Original Message :

WTNT25 KNHC 201444
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC WED NOV 20 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 21.1N 61.7W AT 20/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST OR 280 DEGREES AT 6 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT.......100NE 140SE 0SW 70NW.
12 FT SEAS..210NE 150SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 21.1N 61.7W AT 20/1500Z
AT 20/1200Z CENTER WAS LOCATED NEAR 20.8N 61.7W

FORECAST VALID 21/0000Z 22.0N 61.7W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 140SE 0SW 70NW.

FORECAST VALID 21/1200Z 23.7N 60.2W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 40NE 50SE 0SW 30NW.
34 KT...100NE 140SE 0SW 70NW.

FORECAST VALID 22/0000Z 26.3N 57.2W
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 70SW 70NW.

FORECAST VALID 22/1200Z 29.8N 52.5W...POST-TROP/EXTRATROP
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 50SE 30SW 30NW.
34 KT...100NE 140SE 90SW 70NW.

FORECAST VALID 23/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.1N 61.7W

NEXT ADVISORY AT 20/2100Z

$$
FORECASTER LATTO/MELLO

>

2019-11-20 08:39


Original Message :

WTNT45 KNHC 200837
TCDAT5

Tropical Storm Sebastien Discussion Number 4
NWS National Hurricane Center Miami FL AL202019
500 AM AST Wed Nov 20 2019

Deep convection developed closer to the center of Sebastien
around the time of the previous advisory, but northwesterly shear
and dry air have caused it to wane within the past hour or two. A
late arriving ASCAT-C overpass revealed peak winds a little above
40 kt. Given the typical undersampling of that instrument, the
initial intensity has been raised to 45 kt. The shear and dry air
are expected to keep Sebastien's intensity in check today, but by
tonight the upper-level divergence is forecast to increase while the
storm motion and shear vector line up. This is expected to allow
for some strengthening and nearly all of the intensity guidance and
global models predict deepening. The new intensity forecast is
again similar to the previous advisory and lies between the lower
statistical guidance and the more aggressive dynamical models.

Sebastien appears to have turned northwestward with an initial
motion of 305/7 kt. A turn to the north should occur later today,
and then a northeastward motion is predicted to begin by Wednesday
night as the storm is picked up by a deep layer trough moving
eastward across the western Atlantic. The track guidance is in
agreement on this overall scenario but there are some significant
differences in how quickly Sebastien accelerates northeastward. The
GFS, HWRF, and HMON show the storm recurving quickly ahead of
the trough while the ECMWF is quite a bit slower. The NHC track is
a little slower than the previous forecast, but remains close to the
various consensus aids and the latest UKMET ensemble mean.

FORECAST POSITIONS AND MAX WINDS

INIT 20/0900Z 21.0N 61.0W 45 KT 50 MPH
12H 20/1800Z 21.7N 61.5W 45 KT 50 MPH
24H 21/0600Z 23.2N 60.8W 50 KT 60 MPH
36H 21/1800Z 25.3N 58.6W 55 KT 65 MPH
48H 22/0600Z 28.7N 54.4W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 23/0600Z...DISSIPATED

$$
Forecaster Brown

>

2019-11-20 08:38


Original Message :

WTNT35 KNHC 200836
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 4
NWS National Hurricane Center Miami FL AL202019
500 AM AST Wed Nov 20 2019

...SEBASTIEN A LITTLE STRONGER...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...21.0N 61.0W
ABOUT 235 MI...380 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1002 MB...29.59 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Tropical Storm Sebastien was
located near latitude 21.0 North, longitude 61.0 West. Sebastien is
moving toward the northwest near 8 mph (13 km/h). A turn to the
north-northwest and north is expected later today. A turn toward
the northeast with an increase in forward speed is expected tonight
and Thursday.

Maximum sustained winds have increased to near 50 mph (85 km/h)
with higher gusts. Some strengthening is forecast during the next
48 hours. Sebastien is expected to become an extratropical cyclone
in a couple of days and be absorbed by a cold front on Friday.

Tropical-storm-force winds extend outward up to 150 miles (240 km)
from the center.

The estimated minimum central pressure is 1002 mb (29.59 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Brown

>

2019-11-20 08:38


Original Message :

WTNT25 KNHC 200836
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0900 UTC WED NOV 20 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 21.0N 61.0W AT 20/0900Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTHWEST OR 305 DEGREES AT 7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1002 MB
MAX SUSTAINED WINDS 45 KT WITH GUSTS TO 55 KT.
34 KT....... 90NE 130SE 0SW 0NW.
12 FT SEAS..150NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 21.0N 61.0W AT 20/0900Z
AT 20/0600Z CENTER WAS LOCATED NEAR 20.7N 60.9W

FORECAST VALID 20/1800Z 21.7N 61.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 130SE 0SW 0NW.

FORECAST VALID 21/0600Z 23.2N 60.8W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...100NE 130SE 30SW 0NW.

FORECAST VALID 21/1800Z 25.3N 58.6W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...100NE 140SE 30SW 30NW.

FORECAST VALID 22/0600Z 28.7N 54.4W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...120NE 150SE 60SW 30NW.

FORECAST VALID 23/0600Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.0N 61.0W

NEXT ADVISORY AT 20/1500Z

$$
FORECASTER BROWN

>

2019-11-20 02:39


Original Message :

WTNT45 KNHC 200237
TCDAT5

Tropical Storm Sebastien Discussion Number 3
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Tue Nov 19 2019

There hasn't much of a change with Sebastien for most of tonight,
with the center still exposed to the northwest of a large area of
deep convection. Recently, the low-level center appears to be
slowing down and gaining some latitude as convection re-fires near
the center. The initial wind speed will stay 40 kt, pending receipt
of ASCAT data later this evening.

The initial motion has been more to the west during the past few
hours, but a longer-term motion is 290/8. Sebastien should move
generally northwestward on Wednesday, northward on Wednesday night
and much faster to the northeast on Thursday as the storm moves
along the southwestern periphery of the subtropical ridge and then
ahead of an approaching mid-latitude trough. The forecast has been
adjusted westward in the short-term due mostly to the initial
motion, and then eastward in the longer term due to models
suggesting the storm may stay a little more ahead of the cold front
than before. These forecast changes, however, are fairly typical
for a disorganized system.

Sebastien has some chance to intensify by late tomorrow as the shear
vector and the storm motion vector line up around the same time as
the upper-level divergence is forecast to increase. This should
cause the cyclone to strengthen, and the new forecast is closely
aligned with the previous one. Around 48 hours, Sebastien is
expected to become an extratropical cyclone as it is overtaken by a
cold front, and then become absorbed by the larger front on Friday.
The latest NHC wind speed forecast is close to the model consensus,
but below the regional hurricane models.


FORECAST POSITIONS AND MAX WINDS

INIT 20/0300Z 20.7N 60.6W 40 KT 45 MPH
12H 20/1200Z 21.5N 61.5W 40 KT 45 MPH
24H 21/0000Z 22.9N 61.5W 45 KT 50 MPH
36H 21/1200Z 24.4N 59.8W 50 KT 60 MPH
48H 22/0000Z 27.2N 56.5W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 23/0000Z...DISSIPATED

$$
Forecaster Blake

>

2019-11-20 02:38


Original Message :

WTNT35 KNHC 200236
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 3
NWS National Hurricane Center Miami FL AL202019
1100 PM AST Tue Nov 19 2019

...SEBASTIEN FORECAST TO STRENGTHEN ON WEDNESDAY...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.7N 60.6W
ABOUT 235 MI...380 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Sebastien
was located near latitude 20.7 North, longitude 60.6 West. Sebastien
is moving toward the west-northwest near 9 mph (15 km/h). A
gradual turn to the north is expected by late Wednesday followed by
a turn to the northeast with an increase in forward speed
on Thursday.

Maximum sustained winds remain near 45 mph (75 km/h) with higher
gusts. Some strengthening is forecast during the next 48 hours.
Sebastien is expected to become an extratropical cyclone in a couple
of days and become absorbed by a cold front on Friday.

Tropical-storm-force winds extend outward up to 140 miles (220 km)
from the center.

The estimated minimum central pressure is 1004 mb (29.65 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 AM AST.

$$
Forecaster Blake

>

2019-11-20 02:37


Original Message :

WTNT25 KNHC 200235
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 3
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
0300 UTC WED NOV 20 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 20.7N 60.6W AT 20/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 8 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1004 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 90NE 120SE 0SW 0NW.
12 FT SEAS..120NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.7N 60.6W AT 20/0300Z
AT 20/0000Z CENTER WAS LOCATED NEAR 20.4N 60.3W

FORECAST VALID 20/1200Z 21.5N 61.5W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 90NE 120SE 0SW 0NW.

FORECAST VALID 21/0000Z 22.9N 61.5W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 130SE 0SW 0NW.

FORECAST VALID 21/1200Z 24.4N 59.8W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...100NE 140SE 30SW 0NW.

FORECAST VALID 22/0000Z 27.2N 56.5W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...100NE 150SE 60SW 30NW.

FORECAST VALID 23/0000Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.7N 60.6W

NEXT ADVISORY AT 20/0900Z

$$
FORECASTER BLAKE

>

2019-11-19 20:38


Original Message :

WTNT45 KNHC 192035
TCDAT5

Tropical Storm Sebastien Discussion Number 2
NWS National Hurricane Center Miami FL AL202019
500 PM AST Tue Nov 19 2019

The low-level center of Sebastien has been exposed over the past
several hours, as northwesterly shear of 20-30 kt has been pushing
any deep convection off to the southeastern portion of the cyclone.
The initial advisory intensity is being held at 40 kt and is based
on an earlier scatterometer pass that sampled maximum winds of
39 kt.

The initial motion is 305/10 kt. Sebastien is forecast to be steered
to the northwest around a deep-layer ridge over the central Atlantic
through tonight. By Wednesday, the cyclone should turn to the north,
and then accelerate northeastward Wednesday night as the cyclone
gets caught up in the flow between the retreating ridge and ahead of
an approaching cold front. The model guidance remains in good
agreement on this scenario, and the official forecast track keeps
the cyclone over open waters for the duration of its existence.

The shear is not expected to decrease much over the next couple
days while the system remains a tropical cyclone. There may be an
opportunity for some strengthening Wednesday and Wednesday night as
Sebastien turns to the north and northeast and resides under some
favorable upper-level diffluence. By 48 hours, Sebastien is expected
to transition to an extratropical cyclone just ahead of an
approaching cold front. Therefore, additional strengthening
indicated beyond 36 hours should be due to baroclinic processes. The
cyclone should then become absorbed by the cold front by late this
week. The official forecast was adjusted slightly higher from the
previous one at 36 and 48 hours to reflect the anticipated
intensification of the system as it begins its extratropical
transition.


FORECAST POSITIONS AND MAX WINDS

INIT 19/2100Z 20.6N 59.7W 40 KT 45 MPH
12H 20/0600Z 21.3N 60.7W 40 KT 45 MPH
24H 20/1800Z 22.6N 61.9W 45 KT 50 MPH
36H 21/0600Z 24.2N 61.0W 50 KT 60 MPH
48H 21/1800Z 26.0N 58.9W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 22/1800Z...DISSIPATED

$$
Forecaster Latto

>

2019-11-19 20:36


Original Message :

WTNT35 KNHC 192034
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 2
NWS National Hurricane Center Miami FL AL202019
500 PM AST Tue Nov 19 2019

...SEBASTIEN CONTINUES NORTHWESTWARD...
...EXPECTED TO TURN TO THE NORTHEAST LATE WEDNESDAY...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...20.6N 59.7W
ABOUT 275 MI...445 KM NE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Sebastien was
located near latitude 20.6 North, longitude 59.7 West. Sebastien is
moving toward the northwest near 12 mph (19 km/h). A turn to
the north is expected on Wednesday followed by a turn to the
northeast with an increase in forward speed Wednesday night.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours. Sebastien
is expected to become an extratropical cyclone in a couple
of days and will then be absorbed by a cold front late this
week.

Tropical-storm-force winds extend outward up to 105 miles (165 km)
from the center.

The estimated minimum central pressure is 1006 mb (29.71 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Latto

>

2019-11-19 20:35


Original Message :

WTNT25 KNHC 192033
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
2100 UTC TUE NOV 19 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 20.6N 59.7W AT 19/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTHWEST OR 305 DEGREES AT 10 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1006 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 90NE 0SE 0SW 0NW.
12 FT SEAS..120NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.6N 59.7W AT 19/2100Z
AT 19/1800Z CENTER WAS LOCATED NEAR 20.4N 59.4W

FORECAST VALID 20/0600Z 21.3N 60.7W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 90NE 90SE 0SW 0NW.

FORECAST VALID 20/1800Z 22.6N 61.9W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 130SE 0SW 0NW.

FORECAST VALID 21/0600Z 24.2N 61.0W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...100NE 140SE 0SW 0NW.

FORECAST VALID 21/1800Z 26.0N 58.9W...POST-TROP/EXTRATROP
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...100NE 150SE 0SW 0NW.

FORECAST VALID 22/1800Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.6N 59.7W

NEXT ADVISORY AT 20/0300Z

$$
FORECASTER LATTO

>

2019-11-19 15:07


Original Message :

WTNT25 KNHC 191504 CCA
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC TUE NOV 19 2019

CORRECTED GUSTS AT INITIAL TIME

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 20.1N 58.7W AT 19/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1008 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 50 KT.
34 KT....... 90NE 0SE 0SW 0NW.
12 FT SEAS.. 90NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.1N 58.7W AT 19/1500Z
AT 19/1200Z CENTER WAS LOCATED NEAR 19.8N 58.5W

FORECAST VALID 20/0000Z 21.0N 59.2W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 90NE 90SE 0SW 0NW.

FORECAST VALID 20/1200Z 22.2N 60.0W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 130SE 0SW 0NW.

FORECAST VALID 21/0000Z 23.5N 60.0W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 140SE 0SW 0NW.

FORECAST VALID 21/1200Z 25.5N 58.3W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 150SE 0SW 0NW.

FORECAST VALID 22/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.1N 58.7W

NEXT ADVISORY AT 19/2100Z

$$
FORECASTER LATTO

>

2019-11-19 15:03


Original Message :

WTNT45 KNHC 191501
TCDAT5

Tropical Storm Sebastien Discussion Number 1
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Tue Nov 19 2019

Satellite imagery indicates that the overall cloud pattern of the
disturbance has improved since yesterday, and that the low has
become well-defined. In addition, a late-arriving ASCAT-B
scatterometer pass showed 35-38 kt winds extending 90 n mi from the
center in the northeastern quadrant. This pass also revealed that
the low was nearly closed at the surface, and since the
scatterometer may not have resolved the small scale of the low-level
center it is likely that the surface low is indeed closed. Based on
these data, advisories are being initiated on Tropical Storm
Sebastian with an initial advisory intensity of 40 kt.

The depression will not be in an ideal environment for significant
intensification, as it will be battling dry air to its west and
about 20 kt of northwesterly shear for the next couple of days.
However, due to the presence of an upper trough to the west of the
system, a diffluent environment aloft may aid in some slight
strengthening over the next day or so. After that time, the
depression will begin to interact with an approaching cold front,
and some additional intensification may occur due to baroclinic
processes. The cyclone is then expected to become absorbed by the
front in about 48 hours. The various intensity guidance solutions
are in decent agreement, and the official forecast is near the mean
of these forecasts. There are some timing variations among the
models on when the cyclone will become absorbed by the front, and it
is possible that the depression could be absorbed sooner than
indicated.

The initial motion is 330/07 kt. The depression will be steered to
the northwest in the near term around a deep-layer ridge over the
central Atlantic. By Wednesday, the cyclone should turn north, and
then should accelerate northeastward by Wednesday night as the
cyclone gets caught up in the flow between the retreating ridge and
ahead of the approaching cold front. The model guidance is in good
agreement on this scenario, and on the official forecast track the
cyclone will remain over open waters for the duration of its
existence.


FORECAST POSITIONS AND MAX WINDS

INIT 19/1500Z 20.1N 58.7W 40 KT 45 MPH
12H 20/0000Z 21.0N 59.2W 40 KT 45 MPH
24H 20/1200Z 22.2N 60.0W 45 KT 50 MPH
36H 21/0000Z 23.5N 60.0W 45 KT 50 MPH
48H 21/1200Z 25.5N 58.3W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 22/1200Z...DISSIPATED

$$
Forecaster Latto

>

2019-11-19 15:03


Original Message :

WTNT35 KNHC 191500
TCPAT5

BULLETIN
Tropical Storm Sebastien Advisory Number 1
NWS National Hurricane Center Miami FL AL202019
1100 AM AST Tue Nov 19 2019

...TROPICAL STORM SEBASTIEN FORMS...
...EXPECTED TO REMAIN OVER OPEN WATERS...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.1N 58.7W
ABOUT 275 MI...445 KM NE OF THE LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Tropical Storm Sebastien
was located near latitude 20.1 North, longitude 58.7 West. Sebastien
is moving toward the north-northwest near 8 mph (13 km/h). A turn to
the north is expected on Wednesday followed by a turn to the
northeast and an increase in forward speed Wednesday night.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Some slight strengthening is possible over the next day or so.
Sebastien is expected to become absorbed by a cold front in a
couple of days.

Tropical-storm-force winds extend outward up to 105 miles (165 km)
from the center.

The estimated minimum central pressure is 1008 mb (29.77 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Latto

>

2019-11-19 15:00


Original Message :

WTNT25 KNHC 191457
TCMAT5

TROPICAL STORM SEBASTIEN FORECAST/ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202019
1500 UTC TUE NOV 19 2019

THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.

TROPICAL STORM CENTER LOCATED NEAR 20.1N 58.7W AT 19/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1008 MB
MAX SUSTAINED WINDS 40 KT WITH GUSTS TO 40 KT.
34 KT....... 90NE 0SE 0SW 0NW.
12 FT SEAS.. 90NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.1N 58.7W AT 19/1500Z
AT 19/1200Z CENTER WAS LOCATED NEAR 19.8N 58.5W

FORECAST VALID 20/0000Z 21.0N 59.2W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 90NE 90SE 0SW 0NW.

FORECAST VALID 20/1200Z 22.2N 60.0W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 90NE 130SE 0SW 0NW.

FORECAST VALID 21/0000Z 23.5N 60.0W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 140SE 0SW 0NW.

FORECAST VALID 21/1200Z 25.5N 58.3W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...100NE 150SE 0SW 0NW.

FORECAST VALID 22/1200Z...DISSIPATED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.1N 58.7W

NEXT ADVISORY AT 19/2100Z

$$
FORECASTER LATTO

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