000 AXNT20 KNHC 200604 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST WED NOV 20 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 FEATURE... THE CENTER OF SUBTROPICAL STORM MELISSA AT 20/0300 UTC IS NEAR 33.6N 52.4W...ABOUT 1165 KM/630 NM...TO THE EAST OF BERMUDA. MELISSA IS MOVING NORTHEASTWARD 15 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KNOTS WITH GUSTS TO 55 KNOTS. PUBLIC ADVISORIES ON SUBTROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4. FORECAST/ADVISORIES ON SUBTROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT24 KNHC AND UNDER AWIPS HEADER MIATCMAT4. LARGE SWELLS WILL CONTINUE TO AFFECT BERMUDA...SECTIONS OF THE NORTHERN LEEWARD ISLANDS...PUERTO RICO...HISPANIOLA...AND THE SOUTHEASTERN BAHAMAS DURING THE NEXT COUPLE OF DAYS...CAUSING LIFE- THREATENING SURF AND RIP CURRENTS. PLEASE REFER TO STATEMENTS FROM YOUR LOCAL WEATHER SERVICE OFFICE FOR MORE DETAILS. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 34N TO 35N BETWEEN 51W AND 52W. WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 31N TO 34N BETWEEN 51W AND 55W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...FOR MORE DETAILS ABOUT THE WINDS AND SEA HEIGHTS THAT ACCOMPANY SUBTROPICAL STORM MELISSA. A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS IN THE ATLANTIC OCEAN THROUGH 34N52W TO 26N54W AND 20N58W...INTO THE SOUTHEASTERN CORNER OF THE CARIBBEAN SEA NEAR 13N64W...BEYOND 9N69W IN VENEZUELA. CYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE WEST OF 32N43W 17N50W 9N60W. UPPER LEVEL SOUTHWESTERLY WIND FLOW IS STREAMING FROM CENTRAL VENEZUELA...BEYOND 18N54W IN THE ATLANTIC OCEAN. AN UPPER LEVEL RIDGE IS ALONG 4N51W 16N45W 25N41W BEYOND 32N38W. A SURFACE TROUGH IS ALONG 28N51W 23N54W 19N56W 15N56W. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 12N TO 20N BETWEEN 45W AND 50W. SCATTERED MODERATE TO ISOLATED STRONG ELSEWHERE WITHIN 150 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 32N43W TO 24N46W TO 8N50W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES ACROSS COASTAL GUINEA NEAR 8N13W TO 7N15W. THE ITCZ CONTINUES FROM 7N15W TO 5N20W 5N28W 3N34W AND 3N40W. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG WITHIN 60 TO 120 NM ON EITHER SIDE OF 5N10W 5N16W 5N23W 4N30W 6N36W 8N39W. RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE SOUTH OF 10N TO THE EAST OF 60W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL RIDGE EXTENDS FROM EL SALVADOR... THROUGH THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...ACROSS WESTERN CUBA...SOUTHEASTERN FLORIDA...BEYOND 32N77W IN THE ATLANTIC OCEAN. MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY TO WESTERLY WIND FLOW COVERS THE GULF OF MEXICO. THE BASE OF A MIDDLE LEVEL TO UPPER LEVEL TROUGH REACHES 34N58W IN THE ATLANTIC OCEAN. THE TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 32N66W IN THE ATLANTIC OCEAN JUST TO THE WEST OF BERMUDA...TO 30N70W...TO THE FLORIDA EAST COAST NEAR 28N80W. A STATIONARY FRONT CONTINUES FROM 28N80W TO 26N86W IN THE EASTERN GULF OF MEXICO...TO 26N94W AND 26N102W IN MEXICO. BROAD SURFACE LOW PRESSURE WITH A NORTHWEST-TO-SOUTHEAST ORIENTED TROUGH COVERS THE AREA FROM THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO TO THE WEST CENTRAL GULF ALONG THE MEXICO GULF COAST. MULTILAYERED CLOUDS AND ISOLATED MODERATE CONVECTIVE PRECIPITATION ARE TO THE NORTH OF 22N98W 23N90W 26N82W. A SURFACE TROUGH IS ALONG 28N76W 26N79W 24N81W...FROM THE ATLANTIC OCEAN...ACROSS THE NORTHERN BAHAMAS...TO THE FLORIDA KEYS/ FLORIDA STRAITS. A SURFACE RIDGE PASSES THROUGH NORTHERN LOUISIANA INTO EAST TEXAS...THROUGH THE DEEP SOUTH OF TEXAS...BRIDGING THE STATIONARY FRONT...AND TO 20N97W IN THE COASTAL PLAINS OF MEXICO. FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N TO THE WEST OF 88W... LOW CLOUD CEILINGS ARE OBSERVED AT THE FOLLOWING ICAO STATIONS...KMZG...KBBF...KBQX...KVAF...KEMK...KGUL...KHQI...AND KGBK. MIDDLE LEVEL CEILINGS ARE BEING OBSERVED AT THE FOLLOWING ICAO STATIONS KGUL...KEHC...AND KGBK. LOW CLOUD CEILINGS COVER TEXAS FROM BAY CITY SOUTHWARD TO THE DEEP SOUTH OF TEXAS. MIDDLE LEVEL CLOUD CEILINGS COVER THE FLORIDA PANHANDLE IN MARY ESTHER...IN PARTS OF THE PANAMA CITY AREA...AND IN APALACHICOLA. HIGH LEVEL CLOUD CEILINGS ARE AT THE NAVAL AIR STATION IN PENSACOLA FLORIDA. LOW CLOUD CEILINGS AND HIGH CLOUD CEILINGS COVER THE TAMPA METROPOLITAN AREA. LOW CLOUD CEILINGS ARE IN SARASOTA...PUNTA GORDA...AND CLEARING SOUTHWARD TO NAPLES AND MARATHON KEY. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT4/FZNT24 KNHC...FOR MORE DETAILS ABOUT THE STATIONARY FRONT FROM 27N83W TO 27N90W TO 26N97W. EXPECT NORTHEAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS LOWER THAN 8 FEET TO THE NORTH OF THE FRONT TO THE WEST OF 90W. ...HISPANIOLA... LARGE SWELLS FROM SUBTROPICAL STORM MELISSA WILL CONTINUE TO AFFECT HISPANIOLA...PUERTO RICO...SECTIONS OF THE NORTHERN LEEWARD ISLANDS...AND THE SOUTHEASTERN BAHAMAS DURING THE NEXT COUPLE OF DAYS...CAUSING LIFE-THREATENING SURF AND RIP CURRENTS. PLEASE REFER TO STATEMENTS FROM YOUR LOCAL WEATHER SERVICE OFFICE FOR MORE DETAILS. A SURFACE TROUGH IS ALONG 19N73W IN THE WESTERN SECTIONS OF HAITI...ACROSS SOUTHWESTERN HAITI...TO 17N75W AND TO 15N76W. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 14N TO 18N BETWEEN 72W AND 76W. MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW IS MOVING ACROSS HISPANIOLA. THIS WIND FLOW IS RELATED TO THE CYCLONIC WIND FLOW THAT IS MOVING AROUND THE TROUGH THAT IS PART OF SUBTROPICAL STORM MELISSA. COMPARATIVELY DRIER AIR...APPARENT IN WATER VAPOR SATELLITE IMAGERY...ALSO COVERS HISPANIOLA. SCATTERED TO BROKEN LOW LEVEL AND MIDDLE LEVEL CLOUDS AND POSSIBLE RAINSHOWERS COVER HISPANIOLA. CONVECTIVE PRECIPITATION...BROKEN LOW LEVEL TO MIDDLE LEVEL CLOUDS AND ISOLATED MODERATE TO LOCALLY STRONG FROM 12N TO 18N BETWEEN 71W AND 80W. THE GFS FORECAST FOR 250 MB SHOWS THAT NORTHWESTERLY WIND FLOW WILL PASS ON TOP OF HISPANIOLA DURING THE NEXT 48 HOURS. A TROUGH WILL CUT ACROSS THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA TOWARD THE NETHERLANDS ANTILLES FOR THE ENTIRE TIME. THE GFS FORECAST FOR 500 MB SHOWS THAT NORTHERLY WIND FLOW WILL PASS ON TOP OF HISPANIOLA FOR THE NEXT 48 HOURS. AN ANTICYCLONIC CIRCULATION CENTER WILL BE IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA FOR THE ENTIRE TIME. THE GFS FORECAST FOR 700 MB SHOWS THAT HISPANIOLA WILL START WITH WEAK TO SLIGHTLY ANTICYCLONIC WIND FLOW FOR THE FIRST 12 TO 18 HOURS. CYCLONIC WIND FLOW WITH AN INVERTED TROUGH WILL COVER THE AREA FOR MOST OF THE REST OF THE FORECAST PERIOD...UNTIL THE LAST 6 HOURS OR SO WHEN ANTICYCLONIC WIND FLOW RETURNS. THE REST OF THE CARIBBEAN SEA... A MIDDLE LEVEL TO UPPER LEVEL RIDGE EXTENDS FROM EL SALVADOR... THROUGH THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...ACROSS WESTERN CUBA...SOUTHEASTERN FLORIDA...BEYOND 32N77W IN THE ATLANTIC OCEAN. A SURFACE TROUGH IS ALONG 11N77W 12N80W 15N83W NEAR THE NORTHEASTERN COAST OF NICARAGUA. CONVECTIVE PRECIPITATION... SCATTERED MODERATE TO ISOLATED STRONG TO THE NORTH OF 16N TO THE WEST OF 83W. MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE AREA THAT IS TO THE EAST OF 75W. THE CYCLONIC WIND FLOW IS ASSOCIATED WITH THE WIND FLOW THAT IS MOVING AROUND SUBTROPICAL STORM MELISSA IN THE ATLANTIC OCEAN. MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA THAT IS TO THE WEST OF 75W. THE REST OF THE ATLANTIC OCEAN... A SURFACE RIDGE PASSES THROUGH A 1028 MB HIGH PRESSURE CENTER THAT IS NEAR 33N26W...TO 28N34W 23N39W 17N45W AND 10N49W. THIS RIDGE IS TO THE EAST OF SUBTROPICAL STORM MELISSA. SURFACE ANTICYCLONIC WIND FLOW MOVES AROUND A 1014 MB HIGH PRESSURE CENTER THAT IS NEAR 26N70W...BETWEEN THE 28N51W 23N54W 19N56W 15N56W SURFACE TROUGH AND THE 28N76W 26N79W 24N81W SURFACE TROUGH. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...FOR MORE DETAILS ABOUT THE WINDS AND SEA HEIGHTS THAT ACCOMPANY SUBTROPICAL STORM MELISSA. A SECOND AREA OF INTEREST CONSISTS OF A COLD FRONT FROM 31N69W TO 28N81W. EXPECT NORTH TO NORTHEAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS TO 9 FEET TO THE NORTHWEST OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT