[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 070608
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
0605 UTC Thu Dec 7 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 0000 UTC surface analysis and satellite imagery through
0500 UTC.

...SPECIAL FEATURE...

Atlantic Ocean Gale Warning...

A primary cold front curves southwestward from east of Bermuda
across 31N62W across the Turk and Caicos Islands to beyond the
eastern tip of Cuba. Scattered moderate convection is seen near
and up to 100 nm east of this front. A secondary cold front
extends southwestward from near Bermuda across 31N67W across the
northwest Bahamas to beyond the Florida Keys. Widely scattered
showers are noted near this second boundary. Near-gale to gale-
force winds are occurring near and just east of the primary cold
front north of 28N between 60W and 64W, and behind the secondary
cold front north of 28N between 67W and 74W. Seas in these areas
range from 12 to 17 ft. These fronts are expected to merge on
Thursday while moving southeastward toward the central Atlantic.
As a result, these winds and seas will shift eastward into the
central Atlantic through Thursday afternoon. As the combined front
pulls farther eastward and weakens, conditions should begin to
improve Thursday night.

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

...MONSOON TROUGH/ITCZ...

A monsoon trough enters the Atlantic near the Guinea-Bissau/Guinea
border, then extends southwestward to 05N20W. An ITCZ continues
westward from 05N20W across 03N35W to 05N48W. No significant
convection is found near the trough. Scattered moderate convection
is noted up to 200 nm north, and 70 nm south of the ITCZ west of
32W. Strong westerly upper-level flow is streaming thick cirrus
from convection related to the ITCZ across the tropical Atlantic
and Cabo Verde Islands to the Africa coast.

...GULF OF MEXICO...

The tail end of a cold front runs westward from near the Florida
Keys to the central Gulf. A surface trough extends northwestward
from a 1011 mb low southeast of Coatzacoalcos, Mexico across the
western Bay of Campeche to beyond Tampico. Scattered showers are
occurring near these features across the west-central and southern
Gulf, including the Bay of Campeche and Florida Straits. Fresh
ENE winds and seas of 6 to 8 ft are present at the Bay of
Campeche. Gentle to moderate NE to E winds and 3 to 5 ft seas
prevail for the rest of the Gulf.

For the forecast, a 1027 mb high over Texas/Louisiana is building
southeastward into the northern Gulf behind the cold front. As
gradient between the high and the trough gradually decrease
Thursday morning, winds across the southern half of the Gulf will
diminish. Once this high has shifted eastward into the Atlantic
Thursday night, moderate to fresh southerly winds are expected for
most of the basin Fri through Sat. A strong cold front is forecast
to enter the northwestern Gulf Sat evening, then reach from Tampa
Bay, Florida to Cancun, Mexico Sun evening before exiting the
basin by Mon morning. Strong to near-gale force winds are
anticipated behind the front, with gale force winds possible in
the west-central and southwestern Gulf Sat night through Sun
evening.

...CARIBBEAN SEA...

A cold front stretches west-southwestward from the easter tip of
Cuba across the Gulf of Honduras to southern Belize. Widely
scattered showers are evident near and up to 60 nm north of this
feature. A trade-wind regime continues for the remainder of the
basin. Moderate to fresh with locally strong NE winds and seas of
5 to 7 ft exist at the northwestern basin, behind the cold front
including the lee of Cuba. Fresh to strong NE to ENE winds and 7
to 9 ft seas dominate the south-central basin, including the Gulf
of Venezuela. Gentle to moderate NE to ESE winds and seas at 4 to
6 ft prevail elsewhere in the basin.

For the forecast, the front will reach from the northern coast of
Hispaniola to the northern coast of Honduras Thursday night,
where it will remain nearly stationary through Saturday. Fresh
with locally strong NE winds will persist across much of the
northwestern basin. Strong winds will develop in the Windward
Passage Thursday afternoon near the front and then expand across
most of the central and eastern basin by Sat. By late Sun, the
majority of these winds are expected to be over the central basin.
Looking ahead, the next cold front could enter the northwest
Caribbean Sea by early next week.

...ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section at the beginning about
an ongoing Gale Warning.

Besides the two cold fronts and their associated weather mentioned
in the Special Features section, a surface trough just east of
Barbados is causing widely scattered moderate convection from 09N
to 15N between 50W and 58W. Refer to the Monsoon Trough/ITCZ
section for additional convection in the Atlantic Basin.

Outside the Gale Warning areas, fresh to strong SW to NW winds and
seas of 8 to 12 ft are present near the cold fronts from 25N to
28N between 50W and the central Bahamas. Moderate to fresh with
locally strong NW to N winds and 7 to 10 ft seas are noted from
the northwest Bahamas northward west of 74W. Farther south, gentle
to moderate S to SW winds and seas at 4 to 6 ft are seen from 18N
to 25N between 50W and the Greater Antilles/northern Leeward
Islands. For the central and eastern Atlantic, a large 1021 mb
high is supporting gentle to moderate with locally fresh NE to S
to SW winds and 4 to 7 ft seas north of 18N between the Africa
coast and 50W, including the Canary Islands. Near the Cabo Verde
Islands, gentle to moderate NNE to NE winds and seas at 4 to 6 ft
in moderate northerly swell exist from 08N to 20N between the
central Africa coast and 30W. Farther west, moderate to fresh ENE
to ESE winds and 6 to 9 ft seas are found from 05N to 18N between
30W and the Windward Islands. Light to gentle southerly and
monsoonal winds with seas of 3 to 6 ft in gentle to moderate
northerly swell prevail for the remainder of the Atlantic Basin.

For the forecast W of 55W, the merged front mentioned in the
Special Features section will reach from near 31N48W to the
northern coast of Hispaniola Thu evening. Gale force winds and
high seas are expected both ahead of and behind this front, to the
north of 28N through late Thu afternoon. The gale winds will
shift east of 55W Thu afternoon. The front will stall and weaken
along 20N Fri through Sat as strong high pressure builds across
the western Atlantic. The gradient between the strong high
pressure along 31N and lower pressure associated with the stalled
front will induce fresh to strong ENE trade winds south of 23N Fri
through Sun. On Sun, the front will dissipate as fresh to strong
southerly flow sets up over the waters east of northeast Florida
to 69W in advance of the next cold front. This cold front is
expected to move into the offshore waters of Florida late Sun,
followed by fresh to strong W to NW winds. Seas will build both
east and west of this cold front.

$$

Chan
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