[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120527
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Sun Dec 12 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 0000 UTC surface analysis and satellite imagery through
0525 UTC.

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: A strong cold front continues to move
across the Gulf waters, extending from the western Florida
Panhandle to just south of Tuxpan, Mexico. A recent scatterometer
satellite pass depict gale force winds across the adjacent waters
of southern Tamaulipas and northern Veracruz. Seas are up to 12
ft. Winds will diminish below gale force later this morning.
Please refer to the latest High Seas Forecast product issued by
the National Hurricane Center at the website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough is mostly confined to the African continent,
exiting through the coast of Guinea-Bissau near 12N16W and
extending to 07N24W. The ITCZ extends from 07N24W to 04N35W to
01N50W. Isolated moderate convection is observed from 03N to 11N
and E of 23W.

GULF OF MEXICO...

Refer to the section above for details on the Gale Warning in
effect for the western Gulf.

The weather conditions ahead of the aforementioned cold front are
tranquil. A weak surface trough extends from 19N73W to 24N95W,
but it is not producing any significant convection. Strong to near
gale force N-NE winds and seas of 4-8 ft are present behind the
front. Moderate or weaker, except for locally fresh E-NE winds in
the Florida Straits and offshore NW Yucatan, are occurring ahead
of the front. Seas are 2-4 ft in the rest of the basin.

For the forecast, areas of marine fog will likely return later tonight
lowering visibility in the early morning hours along the NE
Gulf. A high pressure ridge extending from the Atlantic to the
central Gulf will continue to shift eastward in response to the
strong cold front that is moving across the NW Gulf. Gale force
winds are expected to continue over the far west Gulf through Sun
12Z. Seas of 11 ft are expected in the wake of the front within
the strongest winds. The front will weaken as it reaches from
central Florida to the SW Gulf Sun and dissipate through Mon.
Fresh to strong east winds will spread westward through the
Straits of Florida and to the eastern Gulf S of 26N Mon through
midweek along with building seas.

CARIBBEAN SEA...

The tight pressure gradient as a result of the 1031 mb subtropical
ridge over the NW Atlantic and lower pressures over northern South
America result in fresh to strong trades in the central and NE
Caribbean Sea. The strongest winds are occurring offshore southern
Hispaniola and offshore NW Colombia, as indicated by a recent
scatterometer satellite pass. Seas of 5-8 ft are present in the
central, SW and eastern Caribbean Sea. A recent altimeter
satellite pass showed 8 ft seas offshore NW Colombia. Moderate or
weaker winds are found in the rest of the basin, except for
locally fresh trades off the lee of Cuba and the Gulf of Honduras.
Seas of 2-5 ft prevail in the NW Caribbean. The weather
conditions remain fairly tranquil due to a dry airmass dominating
the basin.

For the forecast, the pressure gradient between the ridge across the
northern Caribbean and the Colombian/Panamanian low will
continue to support fresh to strong easterly trades over the
south-central Caribbean through the weekend and early next week.
Moderate to fresh trades will prevail elsewhere. High pressure
will continue to strengthen over the western Atlantic through
the forecast period, resulting in pulsing fresh to locally
strong northeast winds and building seas in the Windward
Passage, the lee of Cuba and south of Hispaniola through Thu
night.

ATLANTIC OCEAN...

A broad high pressure regime dominates the tropical Atlantic
anchored by strong subtropical ridges over the north Atlantic. As
a result of the pressure gradient between the subtropical ridges
and lower pressures over NW Africa and the deep tropics, fresh to
strong easterly winds are found mainly S of 26N, with the
strongest winds occurring from 17N to 24N and between 31W and
63W. Strong trades are also noted in the entrance of the Windward
Passage. Seas of 7-10 ft are prevalent over a large area in the
tropical Atlantic, mainly E of 65W and S of 27N. Seas of 4-7 ft
are found elsewhere in the basin.

The Cumbre Vieja volcano, on the island of La Palma in the Canary
Islands, has been erupting since 19 September 2021. Marine and
aviation interests should monitor this ongoing situation by
reading the Volcanic Ash Advisory issued by Meteo- France, at
http://vaac.meteo.fr/volcanoes/la-palma/.

For the forecast west of 65W, high pressure will build across the region producing
moderate to fresh NE to E winds S of 22N, and mainly gentle to
moderate winds N of 22N through tonight. The next cold front will
move off the northeast Florida coast Sun, and reach from near
31N65W to South Florida by Sun night. This front is forecast to
dissipate over the southeastern waters on Mon. High pressure
behind the front will bring fresh to strong northeast to east
winds mainly across the waters south of 27N by Mon night. These
conditions are expected to last through midweek.

$$
DELGADO
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