000 AXNT20 KNHC 130559 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST WED NOV 13 2013 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 0515 UTC. ...SPECIAL FEATURES... A GALE WARNING IS CURRENTLY IN EFFECT THROUGH THE NEXT 48 HOURS AS A COLD FRONT IS ANALYZED FROM THE BIG BEND REGION OF FLORIDA SW TO THE NE MEXICO COAST NEAR 25N97W. THE FRONT IS FORECAST TO CONTINUE PUSHING ACROSS THE GULF OF MEXICO BASIN AND PORTIONS OF THE SW NORTH ATLC WITH GALE FORCE NE WINDS NORTH OF THE FRONTAL BOUNDARY. SEE LATEST HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 09N26W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N26W TO 08N42W. A PAIR OF SURFACE TROUGHS ARE ANALYZED TO THE WEST OF THE AXIS ALONG 45W AND 52W. NO SIGNIFICANT CONVECTION IS NOTED AT THIS TIME ALONG THE ITCZ OR MONSOON TROUGH...AS WELL AS THE SURFACE TROUGHS. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM OVER THE MID- ATLC SEABOARD SW TO BASE OVER THE LOWER MISSISSIPPI RIVER VALLEY NEAR 31N92W. THIS TROUGH SUPPORTS A COLD FRONT ANALYZED FROM THE BIG BEND REGION OF FLORIDA NEAR 30N84W W-SW TO THE NE MEXICO COAST NEAR 25N97W. WHILE NO SIGNIFICANT DEEP CONVECTION IS NOTED ALONG OR TO THE EAST OF THE FRONT...PLENTY OF MIDDLE TO UPPER LEVEL MOISTURE CONTINUES TO ADVECT NORTHEASTWARD FROM OVER MEXICO TO THE FLORIDA PENINSULA AND INTO THE SW NORTH ATLC REGION DUE TO SOUTHWESTERLY UPPER LEVEL FLOW DOMINATING OVER THE BASIN THIS EVENING. OVERCAST SKIES ARE NOTED ON SATELLITE IMAGERY WITH POSSIBLE ISOLATED SHOWERS AS THE COLD FRONT CONTINUES TO SWEEP SOUTHEASTWARD DURING THE OVERNIGHT HOURS INTO WEDNESDAY. THE PRIMARY IMPACT FROM THE FRONT IS GALE FORCE NORTH- NORTHEASTERLY WINDS IN WAKE OF THE FRONT DUE TO A STRONG PRESSURE GRADIENT AND STRONG SURFACE RIDGING BUILDING OVER THE BASIN THROUGH EARLY THURSDAY. THEREAFTER...THE PRESSURE GRADIENT AND ASSOCIATED WIND FIELD WILL RELAX SOMEWHAT WITH WINDS ABOVE 20 KT EXPECTED GENERALLY E OF 90W AND OVER PORTIONS OF THE SW GULF S OF 22N. CARIBBEAN SEA... A BROAD UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE WESTERN CARIBBEAN NEAR 17N79W AND INFLUENCES MUCH OF THE CARIBBEAN WITH DRY AIR AND SUBSIDENCE WITH THE EXCEPTION OF THE FAR SW CARIBBEAN S OF 12N AND THE FAR NW CARIBBEAN IN THE VICINITY OF THE YUCATAN CHANNEL. WATER VAPOR IMAGERY INDICATES UPPER LEVEL DIFFLUENCE INFLUENCES BOTH OF THOSE AREAS GENERATING ISOLATED SHOWERS AND TSTMS GENERALLY S OF 12N W OF 78W AND NW OF A LINE FROM 16N86W TO 22N81W RESPECTIVELY. ANOTHER AREA OF ISOLATED SHOWERS AND TSTMS IS OCCURRING FROM 15N-18N BETWEEN 76W-82W. OTHERWISE...THE REMAINDER OF THE CARIBBEAN BASIN IS UNDER THE INFLUENCE OF THE DRY AND STABLE FLOW ALOFT WITH NO SIGNIFICANT DEEP CONVECTION NOTED ON SATELLITE IMAGERY. ...HISPANIOLA... CURRENTLY A FEW ISOLATED LOW-TOPPED SHOWERS ARE OCCURRING ACROSS THE ISLAND AND THIS ACTIVITY IS EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS INTO THE DAY ON WEDNESDAY. OTHERWISE...DRY AND OVERALL STABLE NORTHERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY WHICH IS ANTICIPATED TO LIMIT ANY SIGNIFICANT DEEP CONVECTION OVER THE NEXT FEW DAYS. ATLANTIC OCEAN... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL TROUGH AXIS LIES INLAND OVER THE MID-ATLC AND SE CONUS THAT SUPPORTS A COLD FRONT ANALYZED FROM 32N77W TO THE SOUTH CAROLINA COAST NEAR 32N81W. A PRE-FRONTAL TROUGH IS NOTED SW OF THE FRONT FROM 33N72W TO 29N78W. UPPER LEVEL SOUTHWESTERLIES CONTINUE TO ADVECT COPIOUS AMOUNTS OF MIDDLE TO UPPER LEVEL MOISTURE FROM OVER THE GULF OF MEXICO TO OVER PORTIONS OF THE SW NORTH ATLC AHEAD OF THE COLD FRONT N OF 25N W OF 55W. WITH PLENTY OF VERTICAL LIFTING DYNAMICS TO WORK WITH ACROSS THE SW NORTH ATLC... ISOLATED SHOWERS AND TSTMS ARE OCCURRING N OF 25N W OF 65W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A 1037 MB HIGH CENTERED WELL NORTH OF THE DISCUSSION AREA NEAR 47N15W. THE RIDGE AXIS EXTENDS FROM THE HIGH SW TO THE AZORES NEAR 39N27W TO 27N50W TO 22N70W. A FEW ISOLATED SHOWERS AND TSTMS ARE NOTED WITHIN THE MOIST SOUTHERLY FLOW OF THE RIDGE N OF 26N BETWEEN 40W-65W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN