000 AXNT20 KNHC 052346 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST MON DEC 05 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 2335 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ BEGINS NEAR THE COAST OF SIERRA LEONE NEAR 8N13W CONTINUING WESTWARD ALONG 6N20W 5N30W 6N40W 7N50W 6N55W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 2N-9N BETWEEN 30W-50W. ...DISCUSSION... GULF OF MEXICO... SW FLOW ALOFT COVERS THE GULF THIS EVENING...AHEAD OF THE UPPER LEVEL TROUGH CURRENTLY MOVING ACROSS THE CENTRAL/EASTERN CONUS. A STRONG JET-STREAK IS ASSOCIATED TO THIS SYSTEM MOVING ACROSS SE TEXAS SUPPORTING A COLD FRONT EXTENDING INTO THE GULF ACROSS THE LOUISIANA COAST ALONG 29N91W TO THE MEXICO COAST ALONG THE CITY OF TAMPICO. STRONG NORTHERLY WINDS IN THE RANGE OF 20 TO 25 KT ARE OBSERVED WEST OF THE FRONT WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. SOUTHERLY WINDS UP TO 20 KT ARE AHEAD OF THE FRONT WITH A FEW SCATTERED SHOWERS MOVING WITH THE FLOW INLAND OVER MISSISSIPPI ...ALABAMA...GEORGIA...AND THE WRN FLORIDA PANHANDLE N OF 27N BETWEEN 86W-90W. THE FRONT IS FORECAST TO SLOWLY MOVE EASTWARD THROUGH THE WEEK AND CLEAR EAST OF THE GULF REGION LATE THURSDAY INTO EARLY FRIDAY AS HIGH PRESSURE BUILDS ACROSS THE SOUTHERN PLAINS AND NW GULF OVER THE WEEKEND. CARIBBEAN SEA... A NARROW UPPER LEVEL TROUGH EXTENDS SOUTHWARD FROM THE ATLC BASIN INTO THE CENTRAL CARIBBEAN. WATER VAPOR IMAGERY INDICATES A VERY DRY AND STABLE AIRMASS ALOFT AROUND AND WEST OF THE UPPER TROUGH PROVIDING MUCH OF THE CARIBBEAN W OF 66W WITH FAIR WEATHER CONDITIONS WITH A FEW CLUSTERS OF LOW TOP SCATTERED SHOWERS ACROSS THE AREA. THE UPPER LEVEL TROUGHING IS PROVIDING DIFFLUENCE ALOFT ACROSS THE FAR ERN CARIBBEAN...GENERATING AN AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS E OF 66W S OF 18N INCLUDING THE LESSER ANTILLES. HEAVY RAINFALL HAS ALREADY FALLEN OVER MUCH OF THIS GROUP OF ISLANDS OVER THE PAST SEVERAL DAYS. CONTINUED RAIN OVER ALREADY SATURATED TERRAIN INCREASES THE CHANCE FOR FLASH FLOODING...ESPECIALLY OVER THE HIGHER TERRAIN. OVER THE NEXT FEW DAYS...THE UPPER LEVEL TROUGH WILL BE SLOW TO MAKE ANY SIGNIFICANT PROGRESS EASTWARD SO FAIR WEATHER IS EXPECTED TO CONTINUE OVER WESTERN PORTIONS OF THE BASIN...WHILE CONTINUED INCREASED CHANCES FOR PRECIPITATION WILL LINGER OVER EASTERN PORTIONS OF THE BASIN THROUGH THURSDAY. ATLANTIC OCEAN... A NARROW UPPER LEVEL TROUGH AXIS EXTENDS SOUTHWARD FROM THE CENTRAL ATLC INTO THE CENTRAL CARIBBEAN SEA. AN UPPER LEVEL LOW IS EMBEDDED IN THIS TROUGHING CENTERED NEAR 26N62W. THIS UPPER LEVEL SYSTEM SUPPORTS A SERIES OF SURFACE TROUGHS EXTENDING ACROSS THE SOUTH CENTRAL ATLC...ONE EXTENDING FROM 27N62W TO 20N64W...THE SECOND ONE EXTENDING FROM 20N56W TO 14N62W...AND THE THIRD ONE FROM 19N48W TO 13N50W. LOW-LEVEL CONVERGENCE AROUND THESE SURFACE FEATURES IN COMBINATION WITH DIFFLUENCE FLOW ALOFT ASSOCIATED TO THE UPPER TROUGH IS GENERATING A BROAD AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS WITHIN 200 NM ON EITHER SIDE OF A LINE EXTENDING FROM 30N47W INTO THE ERN CARIBBEAN ALONG 15N61W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 27N28W BUT HAS MINIMAL IMPACT AT THE SURFACE AS A STRONG RIDGE...ANCHORED BY A 1033 MB HIGH CENTERED OVER THE AZORES NEAR 40N30W...CONTINUES TO INFLUENCE MUCH OF THE EASTERN ATLC E OF 40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA