000 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