[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 292336
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST MON DEC 29 2008

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 7N11W 4N27W 5N36W 2N51W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 3N-8N BETWEEN
24W-35W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD DEEP LAYERED TROUGH IS ACROSS THE ERN CONUS AND SUPPORTS
A COLD FRONT ENTERING THE DISCUSSION AREA NEAR JACKSONVILLE
FLORIDA SW INTO THE GULF TO 28N85W WHERE IT REMAINS STATIONARY
FROM 26N92W TO 24N96W THEN S TO INLAND OVER COASTAL MEXICO JUST
E OF VERACRUZ. OVERCAST LOW-MID CLOUDS WITH POSSIBLE EMBEDDED
ISOLATED SHOWERS ARE WITHIN 120 NM NORTH AND WEST OF THE FRONT.
SOUTH AND EAST OF THE FRONT...THE ERN GULF IS UNDER BROAD AND
WEAK MIDDLE TO UPPER LEVEL RIDGING EXTENDING FROM THE CARIBBEAN.
WATER VAPOR IMAGERY INDICATES MODERATE TO STRONG SUBSIDENCE AND
DRY STABLE AIR COVERING THE GULF TO THE SE OF THE FRONT. THE
FRONTAL BOUNDARY ACROSS THE GULF IS FORECAST TO GRADUALLY WEAKEN
AS SURFACE HIGH PRESSURE BUILDS IN BY THE MIDDLE OF THE WEEK.

CARIBBEAN SEA...
A 1021 MB SURFACE HIGH IS CENTERED IN THE W ATLC NEAR 27N64W AND
CONTINUES TO PRODUCE MODERATE TO FRESH ELY TRADES AND LOW-LEVEL
MOISTURE ACROSS THE BASIN. THE SURFACE HIGH IS SUPPORTED BY MID-
UPPER LEVEL RIDGING THAT EXTENDS ACROSS NRN SOUTH AMERICA AND
THE ENTIRE CARIBBEAN SEA BASIN. THESE TRADE WINDS ARE USHERING
IN PATCHES OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS ACROSS
THE NE CARIBBEAN AND LEEWARD ISLANDS...INCLUDING THE US/UK
VIRGIN ISLANDS AND PUERTO RICO...ALONG WITH AN AREA S OF 15N AND
E OF 72W. ALSO OF NOTE...ISOLATED SHOWERS ARE OBSERVED OVER THE
GULF OF HONDURAS AND OVER INLAND NRN CENTRAL AMERICA.

ATLANTIC OCEAN...
A BROAD DEEP LAYERED TROUGH IS ALONG THE ERN U.S. SEABOARD AND
SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR
32N80W AND EXTENDS ACROSS NRN FLORIDA INTO THE GULF OF MEXICO.
BROKEN LOW-MID LEVEL CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE
OBSERVED WITHIN 60 NM OF THE FRONT. A WEAK PRE-FRONTAL TROUGH
EXTENDS ACROSS THE W ATLC N OF THE BAHAMAS FROM 32N74W TO
27N79W. ELSEWHERE ACROSS THE WRN ATLC W OF 40W...A 1021 MB
SURFACE HIGH IS CENTERED NEAR 27N64W AND COUPLED WITH AN UPPER
LEVEL RIDGE EXTENDING FROM THE CENTRAL CARIBBEAN SEA ACROSS
HISPANIOLA TO BEYOND 32N60W IS PROVIDING THE W ATLC WITH STABLE
ATMOSPHERIC CONDITIONS. A BROAD LONGWAVE TROUGH IS LOCATED OVER
THE E ATLC WITH TROUGH AXIS EXTENDING FROM 32N29W SW TO 20N45W
18N55W. IT SUPPORTS A COLD FRONT THAT ENTERS THE REGION NEAR
32N22W AND EXTENDS SW TO 23N32W. A LARGE AREA OF UPPER LEVEL
DIFFLUENCE IS E OF THE UPPER TROUGH GENERATING SCATTERED
MODERATE CONVECTION N OF 20N AND E OF THE COLD FRONT. BEHIND THE
MAIN FRONT A QUICK NE MOVING 1001 MB LOW IS LOCATED NEAR 30N34W
WITH A SURFACE TROUGH EXTENDING TO 30N32W 27N32W 25N37W.
SCATTERED SHOWERS ARE WITHIN 90 NM E OF THE SURFACE TROUGH.
OVER THE TROPICAL CENTRAL AND E ATLC...VERY STRONG SW UPPER
LEVEL FLOW RESIDES E OF THE UPPER TROUGH AXIS WITH EXTENSIVE
BROKEN TO OVERCAST CLOUDINESS WITH EMBEDDED SCATTERED SHOWERS SE
OF A LINE FROM TRINIDAD TO THE TAIL END OF THE E ATLC COLD
FRONTAL BOUNDARY NEAR 23N32W.

$$
HUFFMAN





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