[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 192319
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Mon Dec 20 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
2300 UTC.

...SPECIAL FEATURES...

Gulf of Mexico Gale Warning: The most recent satellite derived
wind data provide observations of gale force northerly winds over
the western Gulf, behind a cold front that stretches from the
Florida Big Bend to near Tampico, Mexico. The front will move
slowly south through early tonight, with gale force winds behind
it offshore the Mexico coast. Low pressure will form along this
front in the central Gulf early on Mon, then move NE into the SE
U.S. Tue. This will accelerate the front eastward through the
Gulf by Tue night. This low will likely bring gale force winds to
portions of the north-central and NE Gulf of Mexico. Winds and
seas will subside Wed through Thu in the wake of the front, as
weak high pressure builds in across the Gulf. Please, refer
to the latest High Seas Forecast issued by the National Hurricane
Center at the following website:
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for further details.

Gale Warning E of 35W: A low pressure system over the Azores is
forecast to produce gale force winds over Irving area. As a
result, Meteo-France has issued a Gale Warning through 21/00 UTC.
The forecast indicates westerly 8 (Beaufort wind scale) in northern
Irving with severe gusts. For more details, refer to the Meteo-
France High Seas Forecast listed on their website:
www.meteofrance.com/previsions-meteo-marine/bulletin/
grandlarge/metarea2

...MONSOON TROUGH/ITCZ...

The ITCZ extends from the coast of Sierra Leone near 08N13W to
05N30W to the coast of Brazil near 02N51W. Scattered moderate
convection is noted from 04N-07N between 16W-23W. Similar
convection is also seen from 02N-04N between 30W-33W.

...GULF OF MEXICO...

A Gale Warning has been issued for the Gulf of Mexico. Please,
see the Special Features section for details.

A cold front stretches from the Florida Big Bend to near Tampico,
Mexico followed by gale force winds across the western Gulf and
seas of 8-10 ft. Scattered showers and thunderstorms are ahead
of the frontal boundary, affecting mainly the waters from 20N to
26N E of front to about 90W. Mainly light to gentle winds are
observed per scatterometer data ahead of the front over the
eastern Gulf where seas of 3-5 ft prevail.

For the forecast, refer to the Special Features section for more
information.

...CARIBBEAN SEA...

The tight pressure gradient between high pressure located over
the west-central Atlantic near 28N60W and the Colombian/Panamanian
low is still resulting in fresh to strong trade winds across the
central Caribbean Sea, just S of Haiti and Jamaica, with the
strongest winds occurring offshore NW Colombia. Similar wind
speeds are also observed over the northern Leeward Islands and
regional waters, especially N of Guadeloupe with seas there of
7-8 ft. Moderate to fresh winds are elsewhere except in the NW
Caribbean where mainly gentle to moderate winds prevail. Seas
of 8-11 ft dominate the waters E of the Lesser Antilles while
seas of 8-10 ft are over the central Caribbean. Seas of 6-8 ft
are elsewhere S of 18N and E 82W. In the NW Caribbean, seas are
in the 3-5 ft range.

The E Pacific monsoon trough is triggering scattered showers and
isolated thunderstorms over Panama and nearby Caribbean waters.
Some convective activity is also noted over parts of Nicaragua
and western Jamaica. Elsewhwere, patches of low level moisture,
embedded in the trade wind flow, are observed elsewhere producing
isolated to scattered passing showers. An area of low level
clouds with possible showers is moving across the Leeward Islands
into the NE Caribbean Sea.

For the forecast, high pressure building south through the Atlantic
will support fresh to strong trades over the central Caribbean
through tonight. The high will then push east Mon, allowing winds
to diminish. Large N to NE swell will continue in the tropical N
Atlantic as well as Mona and Anegada Passages through Mon night.
Looking ahead, a cold front will reach the Yucatan Channel on
Tue, and extends from west-central Cuba to the Gulf of Honduras
by Tue night.

...ATLANTIC OCEAN...

The above mentioned high pressure located near 28N60W dominates
the central and western Atlantic, the Bahamas and SE Florida.
Scattered showers and thunderstorms are developing E of Florida,
ahead of a cold front currently moving across the Gulf of Mexico.
Farther E, a cold front crosses near the Madeira Islands and
enters the forecast waters near 31N19W to 27N26W. Fresh to strong
winds and seas in the 10-14 ft range are noted in association
with the front. Some shower activity is along the frontal
boundary. Fresh to strong winds are also seen N of the ITCZ to
about 14N between 20W-30W. Fresh to locally strong trades
continues to dominate the tropical Atlantic due to the pressure
gradient between the high pressure previously mentioned and lower
pressures in the vicinity of the ITCZ.

For the forecast W of 65W, the high located near 28N60W is
inducing fresh to strong trades near the Greater Antilles and
mainly gentle to moderate winds elsewhere. These conditions will
improve through Monday as the high shifts to the east and winds
relax. A cold front will move off the SE U.S. coast tonight, then
move east, bringing strong winds on both sides of the front
mainly N of 29N. Low pressure will move NE off the SE U.S. coast
Tue, bringing another potential for strong to near gale winds on
Wed and Thu. Large N swell impacting the Atlantic zones from 19N-
22N between 55W-65W will diminish into tonight.

$$
GR
This weather bulletin was brought to you by:
www.nashvilleweather.net