000 AXNT20 KNHC 120539 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0500 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE ITCZ BEGINS OVER WRN AFRICAN REACHING THE COAST OF GUINEA NEAR 10N14W CONTINUING OVER ATLC WATERS ALONG 7N24W 5N40W. ISOLATED MODERATE CONVECTION IS ALONG THE ITCZ AXIS. ...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. ALOFT...A BROAD UPPER TROUGH COVERS THE SE CONUS WITH AXIS EXTENDING ACROSS THE FLORIDA PANHANDLE AND INTO THE ERN GULF. THIS UPPER TROUGH IS HELPING SUPPORT AN AREA OF WIDESPREAD STRONG SHOWERS/SCATTERED THUNDERSTORMS OVER THE FLORIDA PANHANDLE AND PORTIONS OF GEORGIA FROM 29N-31N BETWEEN 83W-87W. 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 84W-88W...AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS E OF NICARAGUA S OF 15N BETWEEN 76W-84W. SOME OF THIS ACTIVITY IS ALSO INFLUENCED BY LOW LEVEL CYCLONIC FLOW AROUND THE MONSOON TROUGH EXTENDING ACROSS COSTA RICA TO NRN COLOMBIA. A FEW ISOLATED SHOWERS ARE ALSO IN THE NE CARIBBEAN N OF 16N E OF 71W. 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 29N BETWEEN 77W-81W DUE TO DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH WITH AXIS DOWN THE W COAST OF FLORIDA. SURFACE WIND CONVERGENCE MAY ALSO BE ATTRIBUTING TO THE STRONG ACTIVITY. UPPER LEVEL RIDGING IS TO THE E PROVIDING FAIR WEATHER ACROSS THE BAHAMAS. AN UPPER LEVEL LOW NEAR 23N56W IS SUPPORTING A SURFACE TROUGH ALONG 31N62W 26N64W 20N62W. MOST OF THE SHOWER ACTIVITY IS WELL E OF THE TROUGH NEAR THE AREA OF STRONGEST DIFFLUENCE ALOFT. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 17N-26N BETWEEN 48W-57W. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1032 MB HIGH NEAR 35N36W PROVIDING MOSTLY FAIR WEATHER. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 31N42W. 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 ERN 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