000 AXNT20 KNHC 041132 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST TUE DEC 04 2012 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE FAR E TROPICAL ATLC NEAR 7N11W TO 6N14W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 5N31W 6N39W 10N54W TO SOUTH AMERICA NEAR 8N61W. A SURFACE TROUGH EXTENDS FROM 19N49W TO 11N51W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-9N BETWEEN 27W-50W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 10N-15N BETWEEN 45W-61W AND WITHIN 60 NM ALONG THE COAST OF SOUTH AMERICA BETWEEN 56W-61W. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE CONTINUES TO DOMINATE THE GULF THIS MORNING ANCHORED BY A 1026 MB HIGH OFF THE COAST OF SOUTH CAROLINA. AN UPPER RIDGE IS BEING INDUCED OVER THE GULF ALONG 90W IN RESPONSE TO AN UPPER TROUGH DIGGING S FROM THE PLAIN STATES ACROSS TEXAS INTO N MEXICO. SOUTHERLY RETURN FLOW OVER THE NW GULF CONTINUES TO PRODUCE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 27N TO INLAND OVER THE N GULF COAST BETWEEN VERMILION BAY LOUISIANA TO GALVESTON TEXAS. REMNANT MOISTURE IS GENERATING SCATTERED SHOWERS FROM 23N-27N BETWEEN 84W-93W. THE EASTERLY SURFACE FLOW OVER THE SE GULF IS USHERING IN SCATTERED SHOWERS FROM 25N TO THE COAST OF CUBA E OF 83W THROUGH THE STRAITS OF FLORIDA INCLUDING THE FLORIDA KEYS. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS MORNING. FRESH EASTERLY WINDS IN THE SE GULF WILL DIMINISH AS THE SURFACE RIDGE WEAKENS TODAY. A WEAK FRONT WILL MOVE INTO THE NW GULF LATE TONIGHT STALLING OVER THE CENTRAL GULF WED AND DISSIPATING THU. HIGH PRESSURE WILL REBUILD ACROSS THE GULF FROM THE NE FRI AND SAT WITH FRESH SOUTHERLY FLOW EXPECTED IN THE NW GULF. CARIBBEAN SEA... A BROAD UPPER RIDGE IN THE TROPICAL ATLC EXTENDS A RIDGE AXIS ALONG THE N COAST OF SOUTH AMERICA TO OVER S NICARAGUA NEAR 11N84W GIVING THE CARIBBEAN MAINLY SW TO W FLOW ALOFT. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR ALOFT DOMINATE THE CARIBBEAN THIS MORNING. LIGHT TO MODERATE NE TRADE WINDS ACROSS THE CARIBBEAN CONTINUE TO BANK SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS IN THE GULF OF HONDURAS S OF 19N W OF 85W AND WITHIN 150 NM ALONG THE COAST OF NICARAGUA. REMNANT LOW LEVEL MOISTURE IS GENERATING SCATTERED SHOWERS OVER THE NE CARIBBEAN N OF 15N TO OVER THE ISLANDS BETWEEN THE LEEWARD/ VIRGIN ISLANDS AND DOMINICAN REPUBLIC. SIMILAR ACTIVITY IS OVER THE SE CARIBBEAN S OF 13N E OF 65W TO OVER THE WINDWARD ISLANDS. THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY CLEAR SKIES THIS MORNING. THE W ATLC SURFACE RIDGE WILL MAINTAIN LIGHT TO MODERATE NE TRADE WINDS ACROSS MOST OF CARIBBEAN WITH PERIODS OF FRESH TO STRONG WINDS IN THE NW CARIBBEAN AND ATLC PASSAGES THROUGH WED. THE PRESSURE GRADIENT WILL WEAKEN SIGNIFICANTLY THU THROUGH SAT IMPROVING MARINE CONDITIONS. ATLANTIC OCEAN... A SURFACE RIDGE DOMINATES MOST OF THE W ATLC ANCHORED BY A 1026 MB HIGH OFF THE COAST OF SOUTH CAROLINA. THE EASTERLY SURFACE FLOW OVER THE FAR W ATLC IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 28N TO THE COAST OF CUBA W OF 78W TO OVER S FLORIDA. AN UPPER TROUGH CONTINUES TO DIG S INTO THE W/CENTRAL ATLC REINFORCING THE SHORTWAVE UPPER TROUGH THAT EXTENDS FROM 31N56W TO 23N52W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 26N53W THROUGH A 1010 MB LOW NEAR 21N57W TO 18N60W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM OF LINE FROM 22N52W TO 20N56W WITH SCATTERED SHOWERS WITHIN 45 NM OF LINE FROM 20N56W TO THE LEEWARD ISLANDS NEAR 17N62W. AN UPPER RIDGE IS TO THE E EXTENDING FROM 21N44W TO 33N34W PROVIDING DIFFLUENCE ALOFT TO GENERATE DENSE CLOUD COVER WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 22N-32N BETWEEN 45W-56W. AN UPPER TROUGH IS N OF THE DISCUSSION AREA SUPPORTING A COLD FRONT THAT EXTENDS TO 31N36W WHERE A SURFACE TROUGH CONTINUES ALONG 27N40W TO 24N45W. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE WITHIN 120 NM ON EITHER SIDE OF THE TROUGH. A SURFACE RIDGE DOMINATES THE REMAINDER OF THE E ATLC N OF 14N E OF 33W ANCHORED BY A 1033 MB HIGH ESE OF THE AZORES. FRESH TO STRONG NE WINDS IN THE W AND CENTRAL ATLC S OF 27N WILL DIMINISH THROUGH WED NIGHT AS HIGH PRESSURE N OF THE AREA WEAKENS. A WEAK COLD FRONT WILL CLIP THE AREA N OF 30N LATE WED AND THU WITH HIGH PRESSURE REBUILDS FRI AND SAT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW