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Atlantic Tropical Weather Discussion



000
AXNT20 KNHC 180949
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Mon Jan 18 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 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 
0930 UTC.

...SPECIAL FEATURES...

Caribbean Gale Warning: High pressure building north of the area
will continue to support strong to near gale force winds over 
the south-central Caribbean through the middle of the week. 
Overnight land breezes will allow these winds to pulse to gale 
force within 90 nm off the coast of Colombia, mainly between 
Cartagena and Barranquilla. Please read the latest NWS High Seas 
Forecast issued by the National Hurricane Center at website 
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. 

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Sierra Leone at 
09N13W to 05N25W. The ITCZ continues from 05N25W to the coast of 
Brazil near 00N48W. Scattered moderate convection is noted from
04N to 08N between 25W and 30W.

GULF OF MEXICO...

A surface ridge extends from 1021 mb high pressure over the
northwest Gulf through the Straits of Florida. Dry conditions 
prevail over the northwestern portion of the basin, while 
scattered showers are noted across the southeastern portion. 
Recent buoy and platform observations along with scatterometer 
satellite data indicated light to gentle anticyclonic winds 
across most of the basin, while moderate winds are noted near the 
Yucatan Peninsula. Buoy, ship and altimeter data also indicated 
2 to 4 ft. 

The high pressure over the northwest Gulf will shift east across 
the northern Gulf through Fri. Fresh to strong southerly return 
flow will set up over the NW Gulf tonight into Tue between the 
high pressure and lower pressure farther west over northeast 
Mexico. These winds will diminish some by mid week. This pattern
will bring relatively warm and moist are across cooler shelf
waters in the northwest Gulf, allowing the potential for sea fog
by mid week over portions of the northwest and north-central Gulf.
Farther south, a trough will form off the west coast of the 
Yucatan Peninsula each night through Wed night, supporting brief 
pulses of fresh to strong winds. 

CARIBBEAN SEA...

There is a gale warning in effect for the south-central 
Caribbean. Please see the Special Features section above for 
more details.

A dissipating stationary front extends across the northwest 
Caribbean from central Cuba to north-central Honduras. Moderate to
fresh NE winds and 3 to 5 ft seas are noted over the northwest
Caribbean. Gale force winds and 8 to 10 ft seas are noted off
Colombia. Moderate to fresh trade winds are ongoing elsewhere across
the southeast and south- central Caribbean, with 5 to 7 ft seas. 
Regional radars indicated isolated showers across the Windward 
Islands, the ABC Islands and Puerto Rico. Scattered showers are 
likely in the eastern part of the Yucatan Channel.

For the forecast, A stationary front reaching from eastern Cuba to the
Gulf of Honduras will dissipate this morning. High pressure
building in the wake of the front north of the region will bring
increasing winds and building seas over the southeast and south-
central Caribbean, with winds pulsing to gale force off the
coast of Colombia mainly at night through mid week. Fresh to
strong NE winds are also expected in the lee of eastern Cuba
tonight through Wed night. 

ATLANTIC OCEAN...

West of 60W: A weakening cold front extends from near 31N54W to 
27N60W where it then continues as a stationary front through 
eastern Cuba and across western Caribbean. Scattered showers are 
ongoing in broad swath from South Florida across the northern 
Bahamas to 31N75W. These showers are ahead of a developing cold 
front approaching the area from Georgia and the Carolinas. 
Moderate to fresh SW to W winds are evident ahead of this boundary
over the waters north of 27N and west of 70W with 5 to 7 ft seas.
1018 mb high pressure is centered near 29N62W, supporting light to
gentle breezes north of 27N between 60W and 70W. Seas are quite
large in this area however, reaching 7 to 11 ft in lingering NW
swell. Moderate trade winds persist south of 27N with 5 to 7 ft
seas in open waters.

For the forecast, the stationary front extending from 25N65W to 
eastern Cuba will dissipate today ahead of the developing 
reinforcing cold front, expected to move off the NE Florida coast
later this morning. The stronger front will move rapidly east and
extend from Bermuda to central Cuba by tonight, from 24N65W to 
eastern Cuba by late Tue, then stall and dissipate from 23N65W to 
the Windward Passage by late Wed. Another front will move 
southward into waters between NE Florida and Bermuda Wed night. 
The main portion of this front will lift to the northeast of the 
area Thu, leaving a trailing stationary segment to dissipate along
27N by late Thu. This will be followed by yet another front 
moving southward into the waters between Bermuda and NE Florida 
Fri. 

Farther east, the subtropical ridge supports gentle to moderate
winds over the waters north of 20N, and moderate to fresh trades
farther south. A large area of NW to N swell with significant wave
heights reaching 8 to 13 ft are active north of 22N between 30W
and 50W. Farther south, 6 to 8 ft seas prevail in a mix of N swell
and shorter period easterly wind waves.

$$
Christensen