000 AXNT20 KNHC 061747 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N10W TO 04N30W TO 07N48W TO 06N57W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 02N-09N BETWEEN 32W-43W...AND FROM 06N-10N BETWEEN 54W-59W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE AXIS EXTENDS FROM SOUTHERN MEXICO NEAR 17N94W NORTHEASTWARD OVER THE FLORIDA PENINSULA TO BEYOND 32N77W. THIS UPPER LEVEL FEATURE CONTINUES TO SUPPORT A WEAKENING RIDGE AXIS EXTENDING FROM THE SW NORTH ATLC ACROSS THE FLORIDA PENINSULA TO 24N90W IN THE CENTRAL GULF WATERS. MOSTLY FAIR CONDITIONS WITH MODERATE E TO SE WINDS ARE OBSERVED THIS AFTERNOON. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A FRONTAL BOUNDARY ENTERING THE GULF WATERS AS A COLD FRONT ALONG 30N88W TO 25N94W THEN BECOMING STATIONARY TO 19N95W AND INLAND OVER SOUTHERN MEXICO NEAR 19N95W. THE FRONT IS SLOW TO MAKE ANY EASTWARD PROGRESS DUE TO A LACK OF ANY SIGNIFICANT MIDDLE TO UPPER LEVEL FEATURES AT THIS TIME. HOWEVER...A SHARP UPPER LEVEL TROUGH STRETCHES FROM THE GREAT LAKES REGION SOUTHWESTWARD TO NEW MEXICO OVER THE CONUS AND IS EXPECTED TO AID IN MORE PROGRESSIVE MOVEMENT OF THE FRONT WEDNESDAY ACROSS THE GULF. CURRENTLY...ISOLATED SHOWERS ARE OCCURRING WITHIN 45 NM EITHER SIDE OF THE FRONT WITH OVERCAST SKIES PREVAILING ELSEWHERE WEST OF THE FRONT OVER THE REMAINDER OF THE WESTERN GULF. STRONG NORTHERLY WINDS ALSO ACCOMPANY AREAS W OF THE FRONT IN THE RANGE OF 20 TO 25 KT. THE FRONT IS FORECAST TO CLEAR EAST OF THE GULF REGION THURSDAY INTO EARLY FRIDAY AS HIGH PRESSURE BUILDS ACROSS THE COASTAL PLAINS AND NW GULF OVER THE WEEKEND. CARIBBEAN SEA... AN UPPER LEVEL TROUGH EXTENDS SOUTHWARD FROM THE SW NORTH ATLC INTO THE CENTRAL CARIBBEAN WITH AXIS FROM OVER THE MONA PASSAGE NEAR 19N68W TO 15N75W TO A BASE OVER THE SW CARIBBEAN NEAR 14N83W. WEST OF THE UPPER LEVEL TROUGH WATER VAPOR IMAGERY INDICATES VERY DRY AND STABLE NORTHERLY FLOW ALOFT PROVIDING MUCH OF THE WESTERN CARIBBEAN W OF A LINE FROM PUERTO RICO NEAR 18N67W TO CENTRAL PANAMA NEAR 10N79W WITH FAIR SKIES THIS AFTERNOON. AT THE SURFACE...NE WINDS ARE NOTED ON SHIP AND BUOY OBSERVATIONS AS WELL AS MORNING ASCAT PASSES WITH LOW-LEVEL MOISTURE CONVERGENCE SUPPORTING ISOLATED SHOWERS ALONG THE COAST OF NICARAGUA AND COSTA RICA FROM 10N-12N W OF 82W...AND IN THE GULF OF HONDURAS FROM 16N-19N W OF 85W. FARTHER EAST...THE UPPER LEVEL TROUGHING IS PROVIDING AMPLE MIDDLE TO UPPER LEVEL DIFFLUENCE GENERATING AN AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 150 NM EITHER SIDE OF A LINE FROM 10N66W TO 18N60W...INCLUDING THE LESSER ANTILLES. OVER THE NEXT FEW DAYS...THE UPPER LEVEL TROUGH ACROSS THE CENTRAL CARIBBEAN IS FORECAST TO SLOWLY LIFT NORTHWARD INTO THE SW NORTH ATLC WATERS AND 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... AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 32N58W TO AN UPPER LEVEL LOW CENTERED NEAR 22N65W TO 18N68W AND INTO THE CENTRAL CARIBBEAN SEA. THIS TROUGHING SUPPORTS A PAIR OF SURFACE TROUGHS...ONE ANALYZED FROM 15N60W TO 28N49W...AND THE OTHER FROM 19N62W TO 24N68W. THE MORE LENGTHY SURFACE TROUGH FEATURES LOW-LEVEL CONVERGENCE MAXIMIZED EAST OF THE AXIS WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING FROM 16N-29N BETWEEN 45W-60W...AND FROM 11N-20N BETWEEN 56W-62W. MOST OF THIS CONVECTIVE ACTIVITY IS ENHANCED DUE TO MIDDLE TO UPPER LEVEL DIFFLUENCE FOCUSED EAST OF THE UPPER LEVEL TROUGH AXIS. THE OTHER SURFACE TROUGH CONTINUES TO WEAKEN AND IS MORE CLOSELY REFLECTIVE OF ENERGY ROTATING AROUND THE UPPER LEVEL LOW. ISOLATED SHOWERS ARE OCCURRING FROM 21N-26N BETWEEN 58W-67W. OVER THE REMAINDER OF THE SW NORTH ATLC...NE TO E WINDS CONTINUE IN THE RANGE OF 15 TO 25 KT AS A 1026 MB HIGH REMAINS ANCHORED NORTH OF THE DISCUSSION AREA NEAR 38N64W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 30N28W BUT HAS MINIMAL IMPACT AT THE SURFACE AS A RIDGE...ANCHORED BY A 1035 MB HIGH CENTERED N OF THE AZORES NEAR 40N27W...CONTINUES TO INFLUENCE MUCH OF THE EASTERN ATLC E OF 40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN