[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141737
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1805 UTC Wed Dec 14 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 1200 UTC surface analysis and satellite imagery through
1700 UTC.

...SPECIAL FEATURES...

Central Atlantic Gale Warning: A large and powerful low pressure
system centered north of the area near will bring strong to near
gale force W winds tonight through Thu night to the waters east of
65W and north of 27N. Very large seas can be expected in this
area. By Thu night, the forecast calls for W to NW winds of 30-35
kt N of 30N between 47W and 54W with seas of 17-23 ft in NW swell.
Please read the latest High Seas Forecast issued by the National
Hurricane Center at website
https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coast of Sierra Leone near
08N13W to 07N17W. The ITCZ continues from 07N17W to 04N30W to
02N50W. Scattered moderate convection is noted north of the ITCZ
from 03.5 to 06.5N between 24W and 45W.

GULF OF MEXICO...

As of 1500 UTC, a cold front has entered the NW Gulf of Mexico,
and extends from SW Louisiana to NE Mexico. A band of showers and
thunderstorms is associated with the front over the Gulf waters.
Recent scatterometer data and buoys observations indicate fresh
to strong southerly winds over the western Gulf, ahead of the
front, with seas of 6-8 ft N of 22N, and 4-6 ft over the Bay of
Campeche based on altimeter data. A dissipating stationary front
is analyzed over the eastern Gulf, and runs from the Florida
Panhandle to south Florida. Fresh to locally strong SE-S winds
and seas of 4-6 ft are noted on the W side of the latter front.

For the forecast, fresh to strong southerly return flow will
prevail over the central and western Gulf today ahead of the cold
front forecast to reach from Apalachicola, FL to the central Bay
of Campeche early Thu and from Sarasota, FL to the central Bay of
Campeche Thu night before slowing down and beginning to weaken. A
line of strong to severe thunderstorms is expected to accompany
the front today over the NW Gulf, and tonight into Thu across the
north-central and NE Gulf of Mexico. Strong to locally near-gale
force northerly winds are expected immediately behind the front
today in the western Gulf, diminishing to moderate to fresh N
winds behind the front tonight into Thu for the central and
eastern Gulf. The front should become stationary Fri night from
the Florida Keys to the south-central Gulf of Mexico before
weakening further. The front should remain in about the same
position through Sat as a surface trough forms over the SW Gulf.
The gradient between this surface trough and high pressure over
the southern U.S. is likely to induce a large area of fresh to
strong N to NE winds over the central Gulf this weekend.

CARIBBEAN SEA...

Satellite derived wind data provide observations of fresh to
strong trade winds over the south-central Caribbean, near the
coast of Colombia. Fresh to locally strong winds are occurring
just S of Haiti, and in the Gulf of Honduras with mainly fresh E
winds in the Windward passage and downwind to near 77W. Moderate
to locally fresh winds prevail elsewhere. Seas are 6-8 ft in the
south-central Caribbean and 3-6 ft elsewhere, except up to 6-7 ft
in the NE Caribbean passages due to NE swell from the Atlantic.

Strong winds in the upper atmosphere support abundant cloudiness
over the SE Caribbean and the Leeward Islands, particularly S of
Guadeloupe. Some shower activity has been reported in the ABC
Islands. Elsewhere, patches of low level moisture with embedded
showers are moving across the basin in the trade wind flow.

For the forecast, high pressure building east of Florida will
maintain fresh to strong trade winds across the central Caribbean
Sea through Fri, with moderate to fresh winds elsewhere. Large
long-period N to NE swell will continue to propagate through the
NE Caribbean passages and affect the Tropical N Atlantic waters
for much of the week. Another large set of N swell is forecast to
begin propagating through the Tropical N Atlantic waters starting
late on Fri and continue through Sun night.

ATLANTIC OCEAN...

See the Special Features section above for details on a Gale
Warning in the central Atlantic.

A cold front enters the forecast area near 31N50W and continues SW
to the SE Bahamas where it becomes stationary to south Florida.
Scattered showers and thunderstorms are along the frontal boundary
E of 57W. Fresh to locally strong SW winds are N of 29N E of the
front to about 45W based on scatterometer data. Mainly gentle to
moderate winds prevail elsewhere on either side of the front. Seas
of 8-12 ft in N-NE swell follow the front especially E of 60W.
High pressure, with a 1023 mb center located N of area near 33N34W
dominates the eastern Atlantic. A dissipating frontal boundary is
producing strong to near gale force SW-W winds and rough or very
rough seas near the coast of Morocco. Seas of 8-12 ft in NW swell
are noted between the Madeira and the Canary Islands.

An area of showers and thunderstorms is observed E of a surface
trough that extends from 20N56W to 12N58W. The convective activity
covers the waters from 17N-22N between 50W-55W. A diffluent
pattern aloft is helping to induce this convection.

For the forecast west of 55W, the aforementioned cold front will
weaken today as high pressure builds in east of Florida. Large
long-period N to NE swell will continue to affect much of the
area for the next couple of days. Farther west, fresh to strong
southerly winds will develop offshore NE Florida beginning tonight
as a strong cold front approaches the southeastern U.S. coast.
The front is forecast to move off the coast late Thu, reach from
near 31N74W to West Palm Beach, FL early Fri, and from near 31N65W
to the Florida Keys early Sat. Scattered to numerous showers and
thunderstorms are likely to move offshore the Florida coast on
Thu. On Sun, a reinforcing cold front is expected to merge with
it. The merged front is expected to reach from near 31N62W to the
central Bahamas and western Cuba Sun night. The fresh to strong
southerly winds will shift eastward across the northern and
central waters through Sat and exit the area late Sat. Fresh
northwest to north winds will follow in behind the merged front.

$$
GR
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