[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 170907
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Sat Dec 17 2022

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 0600 UTC surface analysis and satellite imagery through
0800 UTC.

...SPECIAL FEATURES...

Eastern Atlantic Ocean Gale Warning: A 1012 mb low near the
Atlantic coast of NW Spain and Portugal is assisting in a tight
pressure gradient across the region. A gale warning is in effect
for the Meteo-France high seas marine zone of Irving until 18/00
UTC, as well as for zones northward. Please read the latest Meteo-
France High Seas forecast at website gmdss.org/II.html for more
details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through coastal Liberia near 06N11W to
06N17W. The ITCZ extends from 06N17W to 04N35W to near the coast
of Brazil at 01S47W. Scattered moderate isolated strong convection
is noted from 01N to 06N between 18W and 33W.

GULF OF MEXICO...

A frontal trough extends through the Straits of Florida to north
of the Yucatan Channel while a stationary front is just to the
north from the Florida Keys to across the western Bahamas.
Scattered showers and thunderstorms are near these features across
the Florida Keys and the Straits of Florida. Surface ridging north
of this area supports moderate to fresh NE-E winds north of the
frontal trough to 26N and east of 90W, along with seas of 3 to 5
ft. A cold front extends from New Orleans to across south-central
Louisiana to across the outer Texas waters. Earlier scatterometer
data showed fresh to strong N winds behind the front with 4 to 6
ft seas. Mainly gentle to moderate easterly winds and 2 to 4 ft
seas prevail across the remainder of the basin, except light and
variable in the SW Gulf near another surface trough just offshore
Veracruz, Mexico.

For the forecast, the frontal trough over the SE Gulf will wash
out today. The cold front from south-central Louisiana to across
the outer Texas coastal waters will shift southeast through Sun
with possible low pressure developing out ahead of it and moving
east. The front will mainly stall along the southeast boundary of
the basin Sun night, except for the western portion which will
extend from near Brownsville, Texas to the western Yucatan
Peninsula. Looking ahead, the western portion of the front will
shift northward across the western Gulf late Mon and Tue while
weak low pressure moves into the northwest Gulf. The low pressure
will shift eastward across the northern Gulf through mid week,
with a trailing cold front moving across the western and central
Gulf.

CARIBBEAN SEA...

High pressure over the Atlantic Ocean extends over the northern
Caribbean. The pressure gradient from this high pressure and the
low pressure in Colombia is giving way to fresh to strong winds in
the central Caribbean north of Colombia to 18N, in addition to
the Gulf of Venezuela. Seas are 6 to 10 ft in this area per recent
altimeter data. Moderate to fresh winds prevail elsewhere, except
gentle to moderate in the northern Caribbean north of 20N. Seas
are 4 to 6 ft in the eastern Caribbean, locally higher through
Atlantic passages due to prolonged NE swell, and 3 to 5 ft in the
northern Caribbean north of 20N.

For the forecast, surface ridging north of the region will
maintain fresh to strong NE to E tradewinds across the central and
SW Caribbean Sea through at least Wed night, reaching near-gale
off Colombia before sunrise today and again tonight. Moderate to
locally fresh winds will prevail in the E Caribbean with gentle to
moderate winds in the W Caribbean. Large, long-period N to NE
swell will continue to move into the tropical Atlantic and through
the Anegada Passage into the northeast Caribbean for the next
several days. A cold front will dissipate as it pushes into the
Yucatan Channel Sun night into Mon.

ATLANTIC OCEAN...

Please read the Special Features section for details on an Eastern
Atlantic Ocean Gale Warning.

A cold front from near Bermuda to northeast of the Bahamas
continues as stationary to the Florida Keys. Fresh to strong winds
and 8-11 ft seas are north of 29N ahead of the front. Ridging
anchored by a 1017 mb high near 26N60W covers the remainder SW N
Atlantic providing light to gentle winds near the high center, and
gentle to moderate winds elsewhere. Large NE swell continues to
impact the northeast half of the SW N Atlantic with seas of 7-13
ft, highest near and along 55W. Seas are 4-7 ft elsewhere
northeast of the Bahamas.

A large gale-force low pressure system north of the area extends
a cold front through 31N33W to 25N44W where it continues as
dissipating to 23N57W. Scattered showers and thunderstorms are
north of 27N within 120 nm ahead of the front. Fresh to strong
winds are north of 27N between 27W and 50W. This system continues
to produce the large NE swell mentioned with seas up to around 23
ft near 31N39W. A ridge extends south of the front along 21N/22N
to the northeast just north of the Canary Islands. Light to gentle
winds are under the ridge. Moderate trades mainly prevail south
of the ridge, except fresh west of 45W, as well as between Africa
and the Cabo Verde Islands. Seas are mainly 6 to 9 ft across the
remainder of the open eastern and central tropical Atlantic
waters.

For the forecast west of 55W, the front will completely stall
from 31N55W to the Straits of Florida by early Sun before
dissipating by late Sun. A stronger cold front will move off the
northeast Florida coast tonight, reach from Bermuda to northwest
Cuba by Sun night, and from 31N55W to central Cuba Mon night
before starting to weaken and stall from 25N55W to the southeast
Bahamas through Tue. Meanwhile, large long-period N to NE swell
will continue to affect the NE half of the area for the next
several days. Looking ahead, low pressure may move from the
eastern Gulf of Mexico across Florida Tue night, then continue to
east of the northern Bahamas through late Wed.

$$
Lewitsky
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