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Atlantic Tropical Weather Discussion



000
AXNT20 KNHC 192349
TWDAT 

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
705 PM EST Tue Nov 19 2019

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through 
2330 UTC.

...SPECIAL FEATURES...

The center of Tropical Storm SEBASTIEN, at 19/2100 UTC, is near 
20.6N 59.7W, or about 240 nm/445 km to the NE of the northern 
Leeward Islands. Sebastien is moving NW, or 305 degrees, 10 
knots. The estimated minimum central pressure is 1006 mb. The 
maximum sustained wind speeds are 40 knots with gusts to 50 
knots. Precipitation: scattered moderate to strong within 250 nm 
of the center in the SE quadrant. Isolated moderate to locally 
strong is elsewhere within 330 nm of the center in the E 
quadrant. The PUBLIC ADVISORIES for SEBASTIEN are available via 
the WMO header WTNT35 KNHC, and via the AWIPS header MIATCPAT5. 
The FORECAST/ADVISORIES for SEBASTIEN are available via the WMO 
header WTNT25 KNHC, and via the AWIPS header MIATCMAT5. 

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 39W/40W, from 13N 
southward, moving W 5 to 10 knots. Precipitation: isolated 
moderate to locally strong within 300 nm to the east of the 
wave, and within 360 nm to the west of the wave.

A Caribbean Sea tropical wave is along 72W, from 20N southward 
moving through the central sections of Hispaniola, moving W 10 
knots. Precipitation: no significant deep convective 
precipitation is apparent with this tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of Sierra 
Leone near 08N12W, to 06N16W. The ITCZ continues from 06N16W, to 
02N26W and 04N34W. Precipitation: widely scattered moderate to 
isolated strong within 400 nm to the north of the ITCZ between 
29W and 34W. Rainshowers are possible elsewhere, within 420 nm 
to the north of the ITCZ, and within 240 nm to the south of the 
ITCZ.   

GULF OF MEXICO...

An upper level trough is moving eastward, out of the area.
An upper level ridge is along 100W, in Mexico still. Upper level 
anticyclonic wind flow is moving into the western parts of the 
Gulf of Mexico.

Broad surface anticyclonic wind flow covers the area. A 1017 mb 
high pressure center is near 29N91W.

Weak high pressure in the western Gulf of Mexico will shift 
northeastward through Wednesday. Fresh to strong SE return flow 
will develop in the NW Gulf of Mexico from Wednesday through 
Thursday. A cold front is expected to move off the Texas coast 
late on Friday. The result will be fresh to strong northerly 
winds behind it, from Friday night into Saturday. The front will 
move across the basin rapidly. The front will begin to weaken, 
as it reaches the far SE Gulf on Saturday night.

CARIBBEAN SEA...

A dissipating stationary front is in the Windward Passage.
A surface trough continues from the Windward Passage, to 17N77W, 
16N80W, and 13N82W. Precipitation: Isolated moderate from 17N to 
21N between 66W and 78W/Jamaica, including around Puerto Rico 
and Hispaniola.

Comparatively drier air in subsidence covers much of the area 
that is from 16N southward from 80W eastward. 

Tropical Storm Sebastien near 20.6N 59.7W 1006 mb at 4 PM EST 
moving NW at 10 kt. Maximum sustained winds 40 kt gusts 50 kt. 
Sebastien will move to 21.3N 60.7W Wed morning, 22.6N 61.9W Wed 
afternoon, 24.2N 61.0W Thu morning, become extratropical and 
move to 26.0N 58.9W Thu afternoon, and dissipate Fri afternoon. 
Elsewhere: a weak trough, that extends from the Windward Passage 
across eastern Jamaica and into the SW Caribbean Sea, will 
dissipate tonight. A 72W tropical wave will weaken, from late 
tonight into Wednesday, as it moves across the central Caribbean 
Sea. Fresh to strong NE winds will prevail through the Windward 
Passage, from Wednesday night through Friday. 

ATLANTIC OCEAN... 

A developing cold front passes through 32N73W, to 30N73W and 
28N75W. A surface trough is along 29N66W 25N71W to Great Inagua 
Island in the SE Bahamas. A dissipating stationary front is 
within 120 nm to the east of the surface trough. The dissipating 
stationary front eventually reaches the Windward Passage.
Precipitation: scattered moderate to isolated strong from 24N to 
26N between 68W and 70W. Isolated moderate elsewhere from 20N 
northward from 60W westward.

Broad surface anticyclonic wind flow spans the Atlantic Ocean, 
elsewhere, from 17N northward, to the northeast of T.S. 
Sebastien. 

Tropical Storm Sebastien near 20.6N 59.7W 1006 mb at 4 PM EST 
moving NW at 10 kt. Maximum sustained winds 40 kt gusts 50 kt. 
Sebastien will move to 21.3N 60.7W Wed morning, 22.6N 61.9W Wed 
afternoon, 24.2N 61.0W Thu morning, become extratropical and 
move to 26.0N 58.9W Thu afternoon, and dissipate Fri afternoon. 
Elsewhere: a weak stationary front extends from near 30N64W to 
near the Windward Passage. This front is expected to dissipate 
tonight. A forming cold front will move quickly across the 
northern waters, from tonight through Wednesday night, with 
fresh to strong W to NW winds developing behind the front. 
Sebastien will become merged into the frontal system by Thursday 
night. High pressure will build across the northern waters from 
Thursday through Saturday. It is possible that a second cold 
front may move off the NE Florida coast late on Saturday night. 

$$
mt