[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 202319
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0005 UTC Sun Dec 20 2020

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 1800 UTC surface analysis and satellite imagery through
2300 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A cold front moving across the Gulf of
Mexico will reach the waters east of northern Florida by early
Monday morning. Currently, the front extends SW from a 1013 mb
low pressure located over the NE Gulf of Mexico near 30N86W to
near Veracruz, Mexico. The low is forecast to strengthen as it
moves northeastward into the western Atlantic. Fresh to strong
winds are expected on either side of the front by early Mon
morning. Then, winds ahead of the front will reach gale-force N
of 28N and within about 90 nm E of the front by early Mon
afternoon. Seas are expected to build up to 12-13 ft within the
area of gale- force winds. The low pressure will move well north
of the area later on Monday as the cold front progresses quickly
eastward across the western Atlantic. By Monday night, winds
will diminish below gale force ahead of the front expected to
reach from near Bermuda to central Cuba at that moment. Please
read the latest High Seas Forecast at
https://www.nhc.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the border of Sierra Leone and
Guinea near 09N13W to 08N17W. The ITCZ continues from 08N17W to
05N30W to 05N42W to the coast of Brazil near 03N51W. Scattered
moderate and isolated strong convection is noted from 04N-07N
between 22W-27W, and from 03N-07N between 31W-39W.

GULF OF MEXICO...

As previously mentioned, a cold front extends SW from a 1013 mb
low pressure located over the NE Gulf of Mexico near 30N86W to
Veracruz, Mexico. The most recent ASCAT pass showed fresh to
strong wind within about 120 nm in the southern semicircle of the
low center as well as near Veracruz. Moderate to fresh winds
follow the front elsewhere. Doppler Radar indicates a band of
showers with embedded thunderstorms ahead of the front
approaching central Florida. Cold air stratocumulus clouds are in
the wake of the front but mainly E of 93W. Low level clouds are
banked-up against the Sierra Madre Mountains in Mexico.

The cold front will reach the SE waters of the Gulf region tonight,
moving across South Florida and the Straits of Florida by Mon
morning. As the front moves SE of the Gulf by early Mon afternoon,
high pressure will be in control of the weather conditions
across the area. As a result, winds and seas will continue to
gradually diminish. The next cold front is forecast to enter the
NW Gulf by Wed evening followed by strong to gale-force winds and
building seas. Gales are expected first near Tampico by early
Thu morning, then near the Veracruz area early Thu afternoon. The
front is forecast to exit the Gulf on Thu night.

CARIBBEAN SEA...

Latest scatterometer data revealed fresh to strong trade winds
over the south-central Caribbean and in the Gulf of Venezuela.
Fresh northeast winds are present south of Hispaniola. These
winds are the result of the pressure gradient between high
pressure located over the western Atlantic and lower pressure
associated with the Colombian/Panamaniam low. These winds will
persist over the south-central Caribbean most of the forecast
period.

Patches of low level moisture, embedded in the trade wind flow,
are noted moving westward across the basin mainly north of about
14N. Isolated to scattered passing showers are possible with
some of these clouds. Northeast winds over the SE Bahamas are
also advecting patches of low-level moisture with possible
isolated showers into eastern Cuba.

A cold front, now moving across the Gulf of Mexico, is forecast
to reach the Yucatan Channel and western Cuba on Mon, then will
extend from central Cuba to northern Belize by Mon night and
gradually weaken from eastern Cuba to the Gulf of Honduras on
Tue. Another and stronger cold front is expected to reach the
Yucatan Channel and western Cuba by Thu night. Fresh to strong
northerly winds will follow the front.

ATLANTIC OCEAN...

A cold front will produce strong to gale force winds across the
western Atlantic on Mon. Please, see the Special Features section
for more details. Fresh to strong southerly winds are already
noted over the waters E of NE Florida ahead of the front.

Farther east, a cold front enters the forecast area near 31N40W,
then continues SW to near 26N53W where it becomes stationary.
Pockets of low level moisture, with embedded showers, are noted
behind the front, including the Bahamas. Mainly low-level clouds
are also noted along the frontal boundary. Moderate to locally
fresh winds are seen per scatterometer data in the wake of the
front, forecast to gradually dissipate W of 50W on Mon.

A ridge prevails over the east Atlantic, anchored by a 1027 mb
high pressure located mid-way between the Madeira Islands and
the Azores. Fresh trade winds are observed along the southern
periphery of the ridge affecting the Cabo Verde Islands and
regional waters.

$$
GR
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