000 AXNT20 KNHC 121115 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST MON DEC 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1100 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF GUINEA-BISSAU NEAR 11N16W CONTINUING SW TO 9N20W. THE ITCZ CONTINUES FROM 9N20W ALONG 5N28W 6N41W. SCATTERED MODERATE CONVECTION IS WITHIN 75 NM OF THE AXIS BETWEEN 19W-42W. ...DISCUSSION... GULF OF MEXICO... SURFACE RIDGING DOMINATES THE ERN CONUS AROUND A PAIR OF 1038 MB HIGHS OVER NEW ENGLAND WITH RIDGE AXIS EXTENDING SW TO ERN TEXAS. THIS PATTERN IS PROVIDING MAINLY ELY FLOW ACROSS THE GULF OF MEXICO TONIGHT WITH WINDS UP TO 15 KTS WITH A FEW SURFACE STATIONS REPORTING 20 KTS. ALOFT...A BROAD UPPER TROUGH COVERS THE SE CONUS WITH AXIS EXTENDING DOWN THE FLORIDA PENINSULA. THIS UPPER TROUGH IS HELPING SUPPORT AN AREA OF WIDESPREAD STRONG SHOWERS/POSSIBLE THUNDERSTORMS OVER NRN FLORIDA AND PORTIONS OF ALABAMA...GEORGIA...AND SOUTH CAROLINA N OF 28N E OF 85W. SCATTERED SHOWERS ARE ALSO OVER NE FLORIDA FROM 28N-31N E OF 83W. THE WRN HALF OF THE BASIN HAS PARTLY CLOUDY SKIES WITH POSSIBLE ISOLATED SHOWERS WITH MOSTLY CLOUDY SKIES AND ISOLATED SHOWERS ALONG THE TEXAS AND MEXICO COASTLINE LIKELY DUE TO WIND CONVERGENCE. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. CARIBBEAN SEA... DRY AIR ALOFT AROUND A BROAD UPPER RIDGE OVER THE CARIBBEAN IS KEEPING MUCH OF THE NRN HALF OF THE BASIN UNDER CLEAR SKIES AND FAIR CONDITIONS. HOWEVER...DUE TO A SHORTWAVE UPPER LEVEL TROUGH EXTENDING FROM SRN MEXICO INTO THE E PACIFIC...UPPER LEVEL DIFFLUENCE IS PRESENT OVER THE AREA JUST E OF CENTRAL AMERICA. THIS IS HELPING PRODUCE ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS N OF HONDURAS FROM 16N-20N BETWEEN 85W-88W...AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 15N BETWEEN 74W-86W. SOME OF THIS ACTIVITY IS ALSO INFLUENCED BY LOW LEVEL CYCLONIC FLOW AROUND THE MONSOON TROUGH EXTENDING ACROSS THE COSTA RICA/PANAMA BORDER TO NRN COLOMBIA. A FEW ISOLATED SHOWERS ARE ALSO IN THE NE CARIBBEAN FROM 15N-17N BETWEEN 64W-74W. EXPECT SHOWERS/THUNDERSTORMS TO REMAIN ACROSS THE FAR WRN CARIBBEAN FOR THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... STRONG SHOWERS/POSSIBLE THUNDERSTORMS ARE OFF THE ERN COAST OF N FLORIDA N OF 28N W OF 77W DUE TO DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH WITH AXIS DOWN THE FLORIDA PENINSULA ALONG WITH SURFACE WIND CONVERGENCE DUE TO GALE FORCE WINDS NOTED OFF THE COAST OF NRN FLORIDA. UPPER LEVEL RIDGING IS TO THE SE PROVIDING FAIR WEATHER ACROSS THE NRN CARIBBEAN AND BAHAMAS. A NOW ELONGATED UPPER LEVEL LOW NEAR 23N57W IS SUPPORTING A SURFACE TROUGH ALONG 30N65W 26N66W 22N66W. MOST OF THE SHOWER ACTIVITY IS WELL E OF THE TROUGH NEAR THE AREA OF STRONGEST DIFFLUENCE ALOFT. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 16N-25N BETWEEN 49W-61W. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1032 MB HIGH NEAR 34N34W PROVIDING MOSTLY FAIR WEATHER. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 31N40W. A NARROW UPPER LEVEL TROUGH IS TO THE E EXTENDING FROM THE CANARY ISLANDS ALONG 21N28W 24N44W. UPPER LEVEL MOISTURE IS BEING DRAWN AROUND THE SERN SIDE OF THIS UPPER TROUGH SUPPORTING AREAS OF UPPER LEVEL CLOUDS. EXPECT THE SURFACE TROUGH IN THE CENTRAL ATLC TO REMAIN SOMEWHAT STATIONARY FOR THE NEXT COUPLE OF DAYS BEFORE MERGING WITH A FRONTAL BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON