[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 252308
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Dec 26 2021

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 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through
2230 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough remains mostly inland along the Guinean
Forests of West Africa. The ITCZ extends from 05N10W near the
coast of Liberia through 06N20W to 01N36W to 01N46W near the
coast of Brazil. Scattered moderate to strong convection is noted
near Brazil from 02S to 05N between 38W to 50W. Scattered moderate
convection is from 02N to 07N between 11W to 23W.

GULF OF MEXICO...

A surface ridge extends from the western Atlantic across the
northern Gulf. This pattern is supporting a fresh southerly
breeze over the northwest Gulf with buoys reporting 6 to 8 ft
seas. Gentle to moderate breezes with 3 to 5 ft seas dominate the
central basin with a gentle breeze and 1 to 2 ft seas in the
northeast Gulf. No shower or thunderstorm activity is currently
observed in the basin.

For the forecast, the ridge extending from high pressure over the
western Atlantic along 25N-26N to the W Gulf will lift northward
through early next week, supporting moderate to fresh southeast
winds over the central and western Gulf. Looking ahead, the high
pressure will move eastward through mid week, allowing winds and
seas to diminish over the central and western Gulf by Wed night.
Mostly gentle winds and slight seas will persist over the
eastern Gulf into Mon, followed by moderate winds and seas
through mid week as high pressure builds from the east.

CARIBBEAN SEA...

A 1020 mb high pressure in the NW Atlantic continues to support
enhanced easterly flow in the Caribbean. An earlier scatterometer
pass indicates moderate NE winds in the eastern Caribbean with
buoys reporting 3-5 ft seas. Winds are moderate to fresh in the
central Caribbean with the strongest winds near the coast of
Colombia. Seas in the area are 4-6 ft. In the northwestern
Caribbean, a gentle to moderate breeze dominates with 3-5 ft seas.
There are three weak surface troughs noted on the analysis. One
in the eastern Caribbean near eastern Venezuela. The other two are
between Jamaica and Cuba. None of these features are producing
significant convection, but isolated showers are noted.

For the forecast, fresh to strong winds will pulse mainly during
overnight hours off Colombia starting tonight. Elsewhere, winds
and seas will diminish through Sun across the basin as high
pressure north of the area shifts eastward. This pattern will
return late Mon as high pressure again builds north of the area
following a cold front moving across the western Atlantic. This
will support moderate to fresh NE to E winds across much of the
basin through mid week.

ATLANTIC OCEAN...

The main feature in the tropical north Atlantic is the tail end of
a cold front extending from 31N42W to 24N51W. A shear line then
continues from 24N51W to 23N71W. Behind this boundary,
anticyclonic flow rotates around a 1020 mb high pressure centered
near 29N62W. An earlier scatterometer satellite pass showed
moderate to fresh northeast winds extend from the boundary to 25N
with 6-8 ft seas. South of 25N and ahead of the front, winds are
gentle to moderate with 4-6 ft seas. The strongest winds in the
basin are found on both sides of the cold front north of 25N.
Scatterometer data revealed strong NW winds extend roughly 300 nm
behind the front and strong SW winds extend roughly 300 nm ahead
of the front. Seas are 8-12 ft in these areas. Farther east, a
1020 mb high pressure will remain stationary and dissipate
through tonight. High pressure building behind the front will move
to the south of Bermuda today, ahead of another front that will
move across the waters between Bermuda and northeast Florida Sun.
Looking ahead, the front will move southeast of the region early
next week as high pressure builds northeast of the northern
Bahamas behind the front. Large N swell with building seas will
follow the front east of 70W Sun through mid week. Farther east, a
1022 mb high pressure centered near 28N22W is maintaining a
gradient with lower pressure near the ITCZ to generate fresh to
locally strong NE winds and 8-10 ft seas in the eastern Atlantic
south of 25N and in the central Atlantic south of 15N. Winds are
gentle to moderate elsewhere.

For the forecast, a weakening front in the form of a shearline
extends from 23N60W to NW Haiti and will remain stationary and
dissipate tonight. High pressure behind the front is just south of
Bermuda, and will slide eastward, ahead of another front that
will move across the waters between Bermuda and northeast Florida
Sun. Looking ahead, the front will move southeast of the region
early next week as high pressure builds northeast of the northern
Bahamas behind the front. Large N swell with building seas will
follow the front east of 70W Sun through mid week.

$$
AReinhart
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