[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 261713
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1213 PM EST Tue Dec 26 2017

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 1200 UTC surface analysis and satellite imagery through
1715 UTC.

...ITCZ/MONSOON TROUGH...
The monsoon trough enters the Atlantic Ocean through Nigeria,
Africa, and extends to 03N06W. The Intertropical Convergence Zone
axis continues from 03N06W to 05N25W to the Equator near 50W.
Scattered moderate convection is from 02N-07N between 24W-43W.

...DISCUSSION...

GULF OF MEXICO...
A weak low pressure has developed along a frontal boundary over
the NW Gulf. As of 1500 UTC...the low center is located near
28N96W with a warm front extending to near 26N91W. The mosaic
Doppler Radar from the SE U.S. shows scattered showers over the NW
Gulf and parts of Louisiana and Texas. Broken to overcast low
clouds and possible isolated showers are observed across the
northern Gulf waters, particularly N of 27N. A recent ASCAT pass
provided observations of moderate to fresh easterly winds just N
of the warm front, and mainly gentle to moderate winds across the
remainder of the western Gulf. A trough also extends from the low
center across the far western Gulf to near 21N96W. Otherwise...the
remainder of the basin is under the influence of a surface ridge
anchored by a 1033 mb high currently centered over North Carolina.
The ridge is providing gentle to moderate easterly winds across
the esatern Gulf. The area of weak low pressure across the NW
Gulf will drift eastward over the next couple of days. The
pressure gradient between the low and high pressure N of area will
bring a slightly stronger N-NE winds on Tuesday night into
Wednesday across the NW Gulf eventually becoming more diffuse by
Thursday as the frontal wave weakens across the north-central and
NE Gulf waters. The next strong cold front is expected to emerge
off the Texas and Louisiana coasts Sunday evening.

CARIBBEAN SEA...
The most recent scatterometer data show fresh to strong winds
across the south-central Caribbean near the coast of Colombia, and
fresh to strong winds across the remainder of the central Caribbean.
Moderate to fresh trades are noted elsewhere across the basin.
Patches of low level moisture embedded in the trade wind flow are
producing isolated to scattered passing showers across the Greater
and Lesser Antilles from time to time. A larger patch of low
clouds is over the NW Caribbean. Little change in this weather
pattern is is expected during the next couple of days. Strong
trades will persist over the Central and SW Caribbean through
Thursday, with near gale-force nocturnal winds near the coast of
Colombia tonight. Fresh to locally strong NE winds are expected
through the Windward Passage this evening. Large E swell, in the
form of 7 to 9 ft seas, will reach the E Atlc passages this
evening, and continue through Thu evening.

...HISPANIOLA...
Low-topped trade wind showers will continue to move across the
island from time to time. Mostly dry and stable conditions are
expected to persist during the next couple of days under the
influence of a middle to upper level ridge and associated strong
subsidence.

ATLANTIC OCEAN...
A cold front enters the discussion area near 31N65W extending SW
to 29N71W, then becomes stationary to the NW Bahamas across the
Florida Keys and into the SE Gulf of Mexico. Mainly low clouds
with embedded isolated showers are associated with the frontal
boundary. The cold front is expected to drift eastward through
Wednesday, and begin to stall and weaken on Thursday. The remainder
of central and eastern Atlantic is under the influence of a
surface ridge anchored by a 1034 mb high centered SW of the
Azores near 36N31W. This system will undergo occasional intensity
fluctuations, resulting in a rather tight pressure gradient
across the waters north of the ITCZ/monsoon trough between the
coast of Africa and the Lesser Antilles through at least
Wednesday. The high will move SE and weaken some on Thursday.
Recent ASCAT passes indicate moderate to fresh winds around the
southern periphery of the ridge east of the Lesser Antilles. Seas
are in the 8-11 ft range within this area of winds based on
several altimeter passes.

For additional information please visit
http://www.hurricanes.gov/marine

$$
GR
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