000 AXNT20 KNHC 070000 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE DEC 06 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 2345 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ AXIS EXTENDS ACROSS THE COUNTRIES OF GHANA...COTE D' IVOIRE...AND LIBERIA AND ENTERS THE ATLC WATERS ACROSS THE SOUTHERN COAST OF SIERRA LEONE NEAR 7N12W...CONTINUING WESTWARD ALONG 5N20W 4N30W 5N40W 8N50W 9N55W. SCATTERED MODERATE CONVECTION IS WITHIN 140 NM EITHER SIDE OF THE AXIS BETWEEN 30W-55W. ...DISCUSSION... GULF OF MEXICO... SW FLOW ALOFT CONTINUES TO COVER THE GULF...AHEAD OF THE UPPER LEVEL TROUGH CURRENTLY MOVING ACROSS THE CENTRAL/EASTERN CONUS. A STRONG JET-STREAK IS ASSOCIATED TO THIS SYSTEM SUPPORTING A NEARLY STATIONARY FRONT EXTENDING INTO THE GULF ACROSS THE WRN FLORIDA PANHANDLE ALONG 30N87W CONTINUING SW TO THE MEXICO COAST ALONG 25N92W TO THE COASTAL CITY OF COATZACOALCOS. STRONG NORTHERLY WINDS IN THE RANGE OF 20 TO 25 KT ARE OBSERVED WEST OF THE FRONT. GALE FORCE WINDS ARE EXPECTED OVER THE NEXT 18 HOURS S OF 21N W OF FRONT GENERATING SEAS 13 TO 15 FT. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT. THE UPPER LEVEL TROUGH IS FORECAST TO RECOVER SPEED OVER THE NEXT 24 HOURS AND HELP THE FRONTAL BOUNDARY TO PICK UP MOMENTUM AND MOVE EASTWARD THROUGH THE REMAINDER OF THE WORK WEEK AND CLEAR EAST OF THE GULF REGION LATE THURSDAY INTO EARLY FRIDAY AS HIGH PRESSURE BUILDS ACROSS THE COASTAL PLAINS AND NW GULF WATERS OVER THE WEEKEND. CARIBBEAN SEA... A NARROW UPPER LEVEL TROUGH EXTENDS SW FROM THE ATLC BASIN INTO THE CENTRAL AND SW CARIBBEAN. THIS FEATURE IS BRINGING A VERY DRY AND STABLE AIRMASS ALOFT WEST OF A LINE EXTENDING FROM 17N63W TO 10N68W PROVIDING MUCH OF THE CARIBBEAN 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 65W S OF 17N 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 21N65W. THIS UPPER LEVEL SYSTEM SUPPORTS A SURFACE TROUGH EXTENDING ACROSS THE SOUTH CENTRAL ATLC TO JUST E OF THE LESSER ANTILLES FROM 28N48W TO A 1008 MB SURFACE LOW NEAR 20N55W TO JUST E OF MARTINIQUE NEAR 14N50W. LOW-LEVEL CONVERGENCE AROUND THESE SURFACE FEATURES IN COMBINATION WITH MIDDLE TO UPPER LEVEL DIFFLUENCE FLOW ASSOCIATED TO THE UPPER TROUGH IS GENERATING A BROAD AREA OF SCATTERED HEAVY SHOWERS AND THUNDERSTORMS WITHIN 200 NM ON EITHER SIDE OF THE SURFACE TROUGH. ACROSS THE REMAINDER OF THE DISCUSSION AREA...A WEAK UPPER LEVEL LOW IS CENTERED NEAR 30N25W WITHOUT ANY IMPACT AT THE SURFACE. A STRONG SURFACE RIDGE ANCHORED BY A 1033 MB HIGH CENTERED NORTH OF THE AZORES NEAR 40N26W CONTINUES TO INFLUENCE MUCH OF THE EASTERN ATLC E OF 40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA