000 AXNT20 KNHC 032325 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT DEC 03 2011 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2230 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ BEGINS NEAR THE COAST OF SIERRA LEONE NEAR 8N13W CONTINUING ALONG 9N16W 5N30W 6N45W. ONLY WEAK ISOLATED CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 21W-30W. ...DISCUSSION... GULF OF MEXICO... SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO AROUND A 1038 MB HIGH OVER VIRGINIA. THIS IS PROVIDING MAINLY 15-20 KT NE-E SURFACE FLOW ACROSS THE BASIN AROUND THE RIDGE WITH STRONGER WINDS UP TO 25 KTS ALONG THE TEXAS COASTLINE. CLUSTERS OF SCATTERED SHOWERS ARE EMBEDDED WITHIN THE ANTI-CYCLONIC FLOW MAINLY FROM 22N-25N BETWEEN 84W-88W...AND FROM 24N-30N BETWEEN 89W-94W. ALOFT...MOSTLY DRY AIR COVERS THE AREA AROUND AN UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM THE ERN BAY OF CAMPECHE TO THE FLORIDA PANHANDLE AND UP THE FAR ERN CONUS. A NARROW SWATH OF UPPER LEVEL MOISTURE LIES ON THE WRN SIDE OF THE UPPER RIDGE BETWEEN THE RIDGE AND AN APPROACHING TROUGH OVER THE WRN CONUS. THIS MOISTURE IS SUPPORTING A FEW UPPER LEVEL CLOUDS OVER THE NW GULF. EXPECT THE SURFACE RIDGE TO REMAIN MOSTLY STATIONARY UNTIL THE NEXT COLD FRONT REACHES THE NW GULF ON MONDAY PUSHING THE RIDGE EWD. CARIBBEAN SEA... MAINLY NELY FLOW COVERS THE WRN HALF OF THE CARIBBEAN AROUND THE SURFACE RIDGE THAT COVERS THE ERN CONUS AND WRN ATLC. ISOLATED SHOWERS ARE EMBEDDED WITHIN THIS FLOW S OF 18W W OF 75W WITH A FEW ISOLATED THUNDERSTORMS NEAR THE MONSOON TROUGH EXTENDING FROM SRN COSTA RICA TO NRN COLOMBIA. DRY AIR ALOFT AROUND A BROAD UPPER LEVEL TROUGH WITH AXIS FROM HISPANIOLA TO THE SW CARIBBEAN NEAR 11N79W IS SUPPRESSING ANY DEEP CONVECTION W OF 70W. E OF 70W...SCATTERED SHOWERS/THUNDERSTORMS COVER THE AREA SE OF A LINE FROM THE LEEWARD ISLANDS NEAR 18N64W TO THE NW COAST OF VENEZUELA NEAR 12N71W. MUCH OF THIS ACTIVITY IS INFLUENCED BY A SURFACE TROUGH EXTENDING FROM 11N66W TO N OF GUADELOUPE NEAR 17N62W CONTINUING INTO THE CENTRAL ATLC. SURFACE CONVERGENCE ALONG WITH UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER TROUGH OVER THE WRN AND CENTRAL CARIBBEAN AND AN UPPER LEVEL RIDGE E OF THE LESSER ANTILLES IS HELPING SUPPORT THE CONVECTIVE ACTIVITY. HEAVY RAINFALL HAS ALREADY FALLEN OVER MUCH OF THIS AREA OVER THE PAST SEVERAL DAYS. CONTINUED RAIN OVER ALREADY SATURATED GROUND INCREASES THE CHANCE FOR FLOODING ESPECIALLY IN HIGHER TERRAIN. EXPECT THE SURFACE TROUGH AND ASSOCIATED MOISTURE TO REMAIN SOMEWHAT STATIONARY FOR THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE IS MOVING OVER THE FAR WRN ATLC WITH AXIS UP THE ERN UNITED STATES SEABOARD SUPPORTING SURFACE RIDGING AROUND A PAIR OF 1038 MB HIGHS OVER VIRGINIA AND MAINE. DRY AIR ALOFT ACCOMPANIES THE UPPER RIDGE AND THE WRN SIDE OF AN UPPER LEVEL TROUGH TO THE E WITH AXIS ALONG 65W WHICH IS PROVIDING MOSTLY FAIR WEATHER. 20-25 KT NE WINDS ARE AROUND THE RIDGE IN THE DISCUSSION AREA. TO THE E...UPPER LEVEL DIFFLUENCE AROUND THE E SIDE OF THE UPPER TROUGH IS HELPING SUPPORT CONVECTION NEAR A SURFACE TROUGH EXTENDING FROM THE NRN LEEWARD ISLANDS AT 17N62W ALONG 24N60W 30N58W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 175 NM E OF THE AXIS...AND WITHIN 75 NM W OF THE AXIS. ANOTHER UPPER LEVEL RIDGE IS TO THE E SANDWICHED BETWEEN THE AFOREMENTIONED UPPER TROUGH AND AN UPPER LEVEL LOW NEAR 28N38W. THE UPPER LOW IS SUPPORTING A SECOND SURFACE TROUGH FROM 31N41W TO 21N41W. SCATTERED SHOWERS ARE WITHIN 380 NM E OF THE AXIS FROM 24N-32N. DIFFLUENCE SE OF THE LOW CENTER IS ALSO SUPPORTING CLOUDY SKIES AND POSSIBLE ISOLATED SHOWERS FROM 11N-20N BETWEEN 20W-34W. EXPECT THE SURFACE TROUGH IN THE CENTRAL ATLC TO REMAIN SOMEWHAT STATIONARY AND CONTINUE TO PRODUCE A LARGE AREA OF SHOWERS/THUNDERSTORMS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON