[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 121718
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...MONSOON TROUGH/ITCZ...

The monsoon trough enters the Atlantic through the coast of
Guinea-Bissau near 11N16W to 09N21W. The ITCZ continues from
09N21W to the coast of Brazil near 02N50W. Scattered moderate
convection is noted south of the monsoon trough to 02N and E of
22W. Further west, another area of scattered moderate convection
is observed north of the ITCZ to 06N and west of 41W.

GULF OF MEXICO...
A cold front continues to move across the northern Gulf waters,
extending from Cedar Key to 27N90W, where as of 15Z, transitions
to a stationary front to 19N96W. Seas of 4-8 ft are present
behind the front with 7 to 11 ft noted across the adjacent
waters of southern Tamaulipas and northern Veracruz where near
gale force N-NE winds are observed. The weather conditions ahead
of the aforementioned cold front are tranquil. Over the SW Gulf,
a surface trough extends from 24N90W to 18N93W, but it is not
producing any significant convection. 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, patchy marine fog will continue to lower
visibility in the early morning hours along the NE Gulf and once
again Tue. Strong N winds will remain through this evening
across the western Gulf W of the aforementioned front. Seas will
reach its peak to 11 ft and begin to subside tonight. The front
will weaken as it reaches from central Florida to the SW  Gulf
tonight and dissipate 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 1032 mb subtropical
ridge over the northern Atlantic and lower pressures over northern
South America is supporting 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, with up 9 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 aforementioned pressure gradient between
the ridge across the northern Caribbean and the Colombian/Panamanian
low will support fresh to strong trades over the south-central
Caribbean through mid 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
the week.

ATLANTIC OCEAN...

The tropical Atlantic remains under the influence of a broad
high pressure regime 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 14N to 24N and
between 30W and 52W. Strong trades are also noted in the entrance
of the Windward Passage. Seas of 7-11 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, the cold front moving southeast
across Jacksonville, Florida is forecast to stall and reach
Central Florida tonight. This front is forecast to dissipate
over the southeastern waters on Mon night. 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.


$$
Nepaul
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