[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231151
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
651 AM EST Sat Nov 23 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 0600 UTC surface analysis and satellite imagery through
0545 UTC.

...SPECIAL FEATURES...

Tropical Storm Sebastien is centered near 27.8N 50.6W at 23/0900
UTC or 1535 nm WSW of the Azores moving ENE at 14 kt. Estimated
minimum central pressure is 997 mb. Maximum sustained wind speed
is 55 kt with gusts to 65 kt. Numerous moderate with isolated
strong convection extend 280 nm in the NE quadrant. Gradual
weakening is anticipated, and Sebastien is forecast to dissipate
early next week. The Public Advisories for Sebastien are available
via AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC. The Forecast/Advisories
for Sebastien are available via the AWIPS/WMO headers MIATCMAT5/WTNT25
KNHC.

...TROPICAL WAVES...

A tropical wave is in the central Atlc along 39W from 11N southward,
moving W at 10-15 kt. Scattered moderate isolated strong convection
is along the wave from 03N-08N between 36W-41W.

A tropical wave is to the SE of the Windward Islands from 03N to
15N with axis near 57W, moving W around 10 kt. No significant
convection is noted along the tropical wave.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal plains of Liberia
near 06N10W to 05N12W. The ITCZ continues from that point to
04N26W to 04N36W, then continues W of a tropical wave from 03N41W
to 02N50W. Scattered moderate to strong convection is seen north
and along the ITCZ from 05N-09N between 26W-38W and from 03N-08N
between and along the ITCZ from 13W-31W. For information on
convection, see the Tropical Waves section.

GULF OF MEXICO...

Cold front is moving SE across the NW Gulf extending from 29N92W
to 22N97W near Tampico, Mexico. A pre-frontal trough has develop
about 80 nm SE of the front from 22N95W to 27N93W. A mix of low
and mid level clouds and areas of fog are present ahead of the
front. Scattered showers and isolated tstorms are developing ahead
of the front from 26N-28N and west of 91W. Except for isolated
showers and patchy fog along the NW Gulf coast, the remainder
basin is under fair weather conditions being supported by a deep-
layered anticyclone centered near the Yucatan Peninsula in the
middle to upper levels. At the surface, the ridge is anchored by a
1019 mb high over the SW N Atlc and provides gentle to fresh
return flow to the gulf as seen in the latest ASCAT pass.

The cold front in the NW Gulf will extend from near Sarasota,
Florida to the central Gulf near 23.5N90W to the SW Gulf near
21N96W by early Sun, stalling and weakening from near the N coast
of Cuba to the Yucatan Channel to the Yucatan Peninsula Mon. High
pressure will build in the wake of the front from W to E, shifting
NE of the basin by early Tue. The next cold front is expected to
move into the NW Gulf by early Wed, weakening and stalling in the
northern Gulf by Wed night.

CARIBBEAN SEA...

A surface trough, remnants of a former tropical wave, is over
the NW Caribbean waters extending from 11N81W to 16N84W. Isolated
tstorms are in the vicinity of this trough. The remnants of a
former cold front are analyzed as a shearline extending from
North of Dominica from 15N61W to 14N74W. Scattered to isolated
tstorms are within 60 nm either side of the shearline. This line
of showers and tstms will gradually move SSE through Sat and then
dissipate. Moderate trades will prevail across the basin through
the weekend, except to strong S of the Dominican Republic this
morning. Winds will increase to moderate to fresh early next week,
then to fresh to strong in the S central and W central portions
Tue night through Wed night as the pressure gradient tightens.

Easterly trades will freshen across the south-central Caribbean
early next week, increasing to strong Tue into Tue night.

ATLANTIC OCEAN...

Please, see the Special Features section above for details on
T.S. Sebastien.

A 1019 mb high pressure controls the SW N Atlantic centered near
28N72W. To the east a cold front is present just west of the T.S.
Sebastein extending from 31N47W to 28N53W then transitions to a
stationary front to 23N55W, continues as a cold front south to
North of Dominica near 15N61W. Scattered showers and isolated
tstorms are seen along the boundary. A surface trough ahead of
the front extends from 16N57W to 23N50W with scattered moderate
convection extending 18N-25N along the trough axis. Further E, a
1021 mb high pressure is in control over the NE Atlantic.

Sebastien will continue to accelerate NE away from the forecast
waters today. High pressure in the wake of the cold front will
dominate the forecast waters today, then shift eastward tonight.
The next cold front will cross the region Sun through Mon,
weakening from near Bermuda to the central Bahamas and N coast of
Cuba Mon night through Tue. High pressure will build in from the W
over the region by mid week.

$$
MMT
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