[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190459
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Tue Dec 19 2023

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 0000 UTC surface analysis and satellite imagery through
0455 UTC.

..SPECIAL FEATURES...

Western Atlantic Gale Warning:
A stationary cold front enters the basin near 31N69W and continues
southwestward to the Windward Islands. A band of showers and
thunderstorms persists along and ahead of the cold front to 65W.
A 1050 mb high pressure system near 45N43W extends southwestward
to the NE Caribbean. The pressure gradient between these features
is supporting near-gale to gale force winds N of 26W and between
61W and the front. Seas are peaking near 16 ft in this area, with
seas in excess of 12 ft covering the waters N of 25N between 60W
and 73W. The front is forecast to reach from 31N69W to Haiti Tue
morning, and from near Bermuda to the N coast of Hispaniola near
20N70W by Wed morning. Strong high pressure will build into the
western Atlantic behind the front Tue night through early Thu to
produce fresh to strong winds, gradually diminishing to moderate
to fresh Thu through Fri.

Central Atlantic Gale Warning:
The pressure gradient between the aforementioned 1050 mb high
centered near 45N43W and a 1011 mb low pressure center near 23N48W
is supporting a large area of near-gale to gale force winds N of
24N between 43W and 57W. Seas over this area are peaking near 22
ft. Seas greater than 12 ft cover the waters N of 20N and between
38W and 60W. Numerous moderate to isolated strong convection is
present from 14N to 24N and between 40W and 46W. The low will
move westward, while the high center moves eastward over the next
couple of days. This will loosen the pressure gradient, and
diminish winds below gale force by the middle of the week.

Please read the latest NWS High Seas and Offshore Waters
Forecasts issued by the National Hurricane Center at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and
https://www.nhc.noaa.gov/marine/offshores.php for more details on
both Gale Warnings.

...MONSOON TROUGH/ITCZ...

The monsoon trough reaches the Atlantic through the coast of
Liberia near 05N09W and continues westward to 03N14W. The ITCZ
extends from 03N14W to 03N33W and to 01N50W. Numerous moderate to
isolated strong convection is observed from the ITCZ to 11N and
between 21W and 35W.

...GULF OF MEXICO...

A 1023 mb high pressure system positioned near the southern Texas
coast allows for dry, continental air to filter across the Gulf
of Mexico. No deep convection is noted in the basin. A recent
scatterometer satellite pass captured moderate to fresh northerly
winds over the eastern half of the Gulf of Mexico. Seas in these
waters are 4-7 ft. Elsewhere, light to gentle winds and slight to
moderate seas prevail.

For the forecast, the aforementioned weather pattern will support
fresh N winds over the E Gulf tonight. Stronger high pressure
will shift eastward across the central U.S. and into the eastern
U.S. Tue through Thu, to produce fresh to strong NE to E winds
across the eastern Gulf, including the Straits of Florida, through
early Fri.

...CARIBBEAN SEA...

A stationary front extends from the entrance of the Windward
Passage to near 13N77W. A few showers are seen on satellite
imagery near this boundary, especially affecting SW Haiti. No deep
convection is evident in the remainder of the Caribbean Sea.

The pressure gradient between the aforementioned front and the
ridge over the Gulf of Mexico sustain fresh to strong northerly
winds west of 77W. The strongest winds are found within 90 nm of
the coast of Nicaragua and NE Honduras. Seas are 7-10 ft south of
18N and between 77W and 85W and 4-7 ft in the rest of the
Caribbean waters west of 77W. The highest seas are found in the SW
Caribbean near 11N81W. In the remainder of the basin, moderate or
weaker winds and moderate seas are prevalent.

For the forecast, the front will remain nearly stationary on Tue,
then drift SE across Hispaniola Wed before gradually dissipating
late Wed. Fresh to strong winds behind this front will become N to
NE Tue night through Wed night. High pressure will build SE
across the western Atlantic Wed night through Fri to produce a
broad area of fresh to strong NE winds in the lee of Cuba and the
Windward Passage. At the same time, fresh to locally strong trades
are expected in the south- central Caribbean, including the Gulf
of Venezuela, mainly at night.

...ATLANTIC OCEAN...

Please read the Special Features section for more on the ongoing
Gale Warnings.

Aside from the areas in the Special Features section, the pressure
gradient between the ridge over the Gulf of Mexico and the frontal
system off the eastern United States sustain fresh to strong NW
winds north of 27N and west of 75W. Moderate or weaker winds are
found in the remaining waters west of 70W. Aside from the 12 ft or
greater seas west of 70W, 8-12 ft are prevalent north of the
Bahamas and east of Florida.

Aside from the area of gale force winds, fresh to near gale force
winds are N of 20N and between 35W and 70W. Farther east, fresh to
strong easterly winds are evident east of 33W and north of 13N.
Moderate or weaker winds are present elsewhere in the basin.
Aside from the area of 12 ft seas, seas greater than 8 ft cover
the waters N of 18N and W of 35W. Seas of 8-11 ft are N of 20N
and E of 35W. Elsewhere, seas of 5-8 ft prevail.

For the forecast W of 55W, a western Atlantic cold front extends
through 31N69W to the Windward Passage. SE to S gale-force winds
are ahead of the front N of 26N and E of front to 66W, and will
diminish below gale-force after midnight. Behind the front, fresh
to strong W winds are noted N of 30N. A band of showers and
thunderstorms persists along and ahead of the cold front to 65W.
The front is forecast to reach from 31N69W to Haiti Tue morning,
and from near Bermuda to the N coast of Hispaniola near 20N70W by
Wed morning. Strong high pressure will build into the western
Atlantic behind the front Tue night through early Thu to produce
fresh to strong winds, gradually diminishing to moderate to fresh
Thu through Fri.

$$
Delgado
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