000 AXNT20 KNHC 212342 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST THU NOV 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... TROPICAL STORM MELISSA IS CENTERED NEAR 40.9N 32.1W AT 21/2100 UTC OR ABOUT 295 NM NW OF THE AZORES MOVING ENE AT 24 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 980 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. ISOLATED MODERATE CONVECTION IS FROM 39N-42N BETWEEN 27W-33W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 07N12W TO 03N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 03N19W TO 03N21W TO 06N28W TO 05N32W TO 07N43W. SCATTERED MODERATE CONVECTION IS FROM 01N-08N BETWEEN 23W-36W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT DOMINATES OVER THE GULF THIS EVENING WITH WATER VAPOR IMAGERY INDICATING MODERATELY MOIST MIDDLE TO UPPER LEVELS WITH MOST CLOUDINESS REMAINING ACROSS THE NORTHEASTERN ONE-THIRD OF THE GULF...INCLUDING MUCH OF THE FLORIDA PENINSULA. OTHERWISE...A SURFACE RIDGE ANCHORED WELL TO THE NE ACROSS THE NEW ENGLAND STATES EXTENDS SW THROUGH THE SE CONUS INTO THE SW GULF PROVIDING E-SE WINDS GENERALLY IN THE RANGE OF 10 TO 15 KT. WHILE THE SURFACE RIDGING IS KEEPING CONDITIONS FAIRLY TRANQUIL...THE ONLY SHOWERS NOTED ARE OCCURRING N OF 26N E OF 89W...WITH EARLY EVENING SEABREEZE SHOWERS AND TSTMS OCCURRING ACROSS THE FLORIDA PENINSULA. EASTERLY FLOW IS EXPECTED TO PERSIST THROUGH LATE FRIDAY WHEN THE NEXT COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA COASTS LATE FRIDAY INTO EARLY SATURDAY WITH N-NE WINDS SPREADING ACROSS THE BASIN THROUGH THE UPCOMING WEEKEND. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER THE SOUTH-CENTRAL CARIBBEAN NEAR 12N74W AND IS PROVIDING MUCH OF THE BASIN W OF 75W WITH SOUTHWESTERLY FLOW ALOFT. OVERALL...WATER VAPOR IMAGERY INDICATES THIS SW FLOW REMAINS RELATIVELY DRY...RESULTING IN MOSTLY CLEAR SKIES AND FAIR CONDITIONS ACROSS THE WESTERN CARIBBEAN. HOWEVER...A SURFACE TROUGH ANALYZED FROM 10N79W TO 17N80W IS PROVIDING WEAK LOW-LEVEL MOISTURE CONVERGENCE PRODUCING LOW-TOPPED ISOLATED SHOWERS AND TSTMS FROM 15N-19N BETWEEN 75W-84W. FARTHER EAST...DRIER CONDITIONS ALOFT PREVAIL WITH NORTHWESTERLY FLOW NOTED ON WATER VAPOR IMAGERY BETWEEN 75W AND A BROAD UPPER LEVEL TROUGH AXIS ALONG 64W. TRANQUIL CONDITIONS ONCE AGAIN PERSIST UNDERNEATH THE STABLE ENVIRONMENT WITH ONLY A FEW AREAS OF ISOLATED LOW-TOPPED SHOWERS OCCURRING ACROSS THE FAR NE AND FAR SE CORNERS OF THE BASIN. LASTLY... TRADES ARE FORECAST TO REMAIN 20 KT OR LESS THROUGH THE REMAINDER OF THE WEEK INTO THE UPCOMING WEEKEND. ...HISPANIOLA... CURRENTLY SKIES REMAIN MOSTLY CLEAR THIS EVENING AS OVERALL TRANQUIL CONDITIONS PREVAIL. WATER VAPOR IMAGERY INDICATES DRY AND STABLE NORTHWESTERLY FLOW ALOFT IS IN POSITION TO STAY FOR THE NEXT FEW DAYS PROVIDING CONTINUED FAIR SKIES. ATLANTIC OCEAN... A MID-LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY IN THE VICINITY OF 31N63W THAT IS PARTIALLY SUPPORTING A COLD FRONT ANALYZED FROM 32N45W SW TO 27N58W THEN WEST TO 27N65W WHERE IT BECOMES STATIONARY TO THE BAHAMAS NEAR 26N78W. THE WESTERN EXTENT OF THE FRONT IS GRADUALLY BECOMING A SHEAR LINE DUE TO STRONGER NE WINDS NOTED ON EARLIER SCATTEROMETER PASSES TO THE NORTH OF THE AXIS ACROSS THE REGION. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT...AND FROM 25N-29N BETWEEN 77W-82W...INCLUDING THE COASTAL WATERS OFF THE FLORIDA PENINSULA AND INLAND PORTIONS AS WELL. TO THE EAST...A PRE-FRONTAL SURFACE TROUGH IS ANALYZED TO THE SE OF THE COLD FRONT FROM 24N46W TO 32N38W AND IS PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS EAST OF THE AXIS WITHIN 240 NM EITHER SIDE OF A LINE FROM 17N46W TO 30N33W. THIS CLOUDINESS AND PRECIPITATION IS LIKELY ENHANCED DUE TO A WEAK UPPER LEVEL TROUGH AXIS ALIGNED FROM 25N45W SW TO A BROAD BASE OVER THE SW CARIBBEAN SEA. ACROSS THE EASTERN ATLC...A VIGOROUS MIDDLE TO UPPER LEVEL LOW IS CENTERED OFF THE COAST OF WEST AFRICA NEAR 16N23W THAT CONTINUES TO ADVECT MOISTURE FROM THE DEEP TROPICS NORTHWARD TO 22N IN A ZONE BETWEEN 10W-25W. ISOLATED SHOWERS AND TSTMS ARE POSSIBLE IN THE AREA COVERING 07N-22N BETWEEN 13W-24W...INCLUDING PORTIONS OF THE CAPE VERDE ISLANDS AND COASTAL WEST AFRICA. OTHERWISE...A SURFACE RIDGE TO THE NORTH ANCHORED BY A 1020 MB HIGH CENTERED NEAR 29N26W IS PROVIDING FAIR CONDITIONS FOR AREAS N OF 22N E OF 32W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN