[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211803
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Thu Dec 21 2023

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
1740 UTC.

...SPECIAL FEATURES...

...Central Atlantic Ocean Significant Swell Event...

A cold front passes through 31N56W to 26N60W, 20N65W, and
through the Mona Passage, to the southern coast and the
SW coast of the Dominican Republic. A 1011 mb low pressure
center is near 23N58W. The sea heights are 12 feet or
higher, and they have been at 12 feet or higher, to the
northwest of the cold front. The forecast is for the sea
heights to become less than 12 feet, and for the overall
area that encompasses the 12 foot seas, to become smaller
with time, later today and tonight. Fresh to strong NE winds
are to the west and to the northwest of the cold front.

The sea heights also are rough, ranging from 10 feet to
12 feet, from 17N northward between 23W and 40W, and from
18N northward between 50W and 60W.

Rough seas, in general, cover the Atlantic Ocean, to the
north of the line from St. Vincent and the Grenadines to
07N54W, 06N46W 04N36W 09N29W, to the coast of Africa near 10N.
Moderate seas cover the rest of the Atlantic Ocean.

Strong NE winds are from 15N to 24N from 28W eastward.

Please read the latest NWS High Seas Forecasts, and the
Offshore Waters Forecasts, that are issued by the National
Hurricane Center, at
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, and
www.nhc.noaa.gov/marine/offshores.php, for more details
about the Very Rough Seas.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the southern sections
of Ghana near 06N along the Prime Meridian, to 04N11W.
The ITCZ continues from 04N11W, to 03N20W 03N30W 02N40W
01N45W. Precipitation: scattered to numerous strong is
from 01S to 01N between 46W and 48W in the coastal plains
and in the coastal waters of Brazil just to the northeast
of Belem. Widely scattered moderate to isolated strong is
within 120 nm to the north of the ITCZ between 23W and
37W. Isolated moderate to locally strong is elsewhere
from 10N southward from 60W eastward.

...GULF OF MEXICO...

An east-to-west surface ridge passes through the northern
half of Mississippi, the northern parts of Louisiana, to
the central sections of Texas from east to west. A small
branch of a ridge extends from the NW corner of the Gulf
of Mexico, to the coastal plains of Mexico near 22N98W.

The GFS model for 700 mb shows that an inverted trough is
in the eastern one-third of the Gulf of Mexico. The GFS
model for 250 mb and for 500 mb shows that upper level
anticyclonic wind flow spans the area. Shallow patches
of moisture are supporting isolated showers throughout
the area.

Fresh to strong NE to E winds are in the eastern half of
the area. Moderate E to SE winds are in the western half
of the area. Moderate seas are in the SE quadrant. Slight
seas cover the rest of the area.

High pressure north of the area is supporting fresh to
strong winds and rough seas over the southeast Gulf. Winds
and seas will diminish through early next week as the high
pressure shifts east, ahead of an approaching cold front.
The cold front will move off the Texas coast Sun night,
and reach from near Apalachicola, Florida to near Poza Rica
in Mexico by Mon night.

...CARIBBEAN SEA...

A cold front passes through 20N65W in the Atlantic Ocean,
through the Mona Passage, to the southern coast and the
SW coast of the Dominican Republic. The front becomes
stationary in the SW part of the Dominican Republic,
to 16N75W 13N76W. The stationary front is dissipating
from 13N76W to the coast of Colombia from 09N to 10N
between 75W and 76W. Precipitation: broken to overcast
multilayered clouds, and isolated moderate, are to the
northwest and to the west of the frontal boundary.
Shallow patches of moisture are supporting isolated
showers throughout the area.

An east-to-west oriented surface trough is from 15N
17N between 81W and 90W. Moderate to rough seas are
in the Yucatan Channel, and between Jamaica and 85W.
Rough seas are reaching the Atlantic Ocean side of
the eastern Caribbean Sea islands, from St. Vincent
and the Grenadines northward. Moderate seas cover
most of the rest of the open waters and the offshore
waters of the Caribbean Sea. The exception is for slight
seas in the SE corner of the area, and in the coastal
waters of the entire area. Strong winds are moving
through the Windward Passage. Strong NE winds are
within 75 nm of the coast of Colombia between 74W
and the dissipating stationary front. Fresh NE winds
are in the rest of the Caribbean Sea from 70W westward.
Mostly moderate to some fresh NE winds are from 70W
eastward.

A stationary front extends from Dominican Republic to
near eastern Panama. Fresh to strong N to NE winds and
seas to 9 ft follow the front, with the strongest winds
in the lee of Cuba and the Windward Passage. The front
will dissipate later today. Building high pressure north
of the area will bring a return to more typical E trade
winds Fri through early next week.

...ATLANTIC OCEAN...

Please, read the SPECIAL FEATURES section, for details
about the Central Atlantic Ocean Significant Swell Event.

A cold front passes through 31N56W to 26N60W, 20N65W, and
through the Mona Passage, to the southern coast and the
SW coast of the Dominican Republic. A 1011 mb low pressure
center is near 23N58W. A surface trough is along 17N53W
13N57W, to 10N62W in NE Venezuela. Precipitation: scattered
moderate to isolated strong is from 21N northward between
45W and the cold front. Isolated moderate to locally strong
is elsewhere from 10N northward between 40W and 60W.

Broad surface anticyclonic wind flow covers the Atlantic
Ocean to the east of the cold front and the 1011 mb low
pressure center. Broad surface anticyclonic wind flow also
is to the west and to the northwest of the cold front. Fresh
to strong anticyclonic wind flow is from 10N northward
in the rest of the Atlantic Ocean that is to the east of the
cold front, and from the ITCZ to 10N between 30W and 50W.
Fresh to moderate winds are in the rest of the Atlantic Ocean.

A cold front extending from near 31N59W to Dominican
Republic will shift east of region by late Fri, except
for the southern portion of the front stalling across
the northern Leeward Islands. Fresh to strong N to
NE winds following the front will diminish through
tonight. Northerly swell will linger into Sun.
Looking ahead, winds and seas will increase Sun night
and Mon from the central Bahamas to northeast Florida
ahead of a cold front approaching from the west.

$$
mt/gr
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