000 AXNT20 KNHC 211204 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURE... THE CENTER OF TROPICAL STORM MELISSA AT 21/0900 UTC IS NEAR 39.1N 38.5W...ABOUT 1005 KM/545 NM...TO THE WEST OF THE AZORES. MELISSA IS MOVING EAST-NORTHEASTWARD 28 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 984 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 45 KNOTS WITH GUSTS TO 55 KNOTS. PUBLIC ADVISORIES ON TROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT34 KNHC AND UNDER AWIPS HEADER MIATCPAT4. FORECAST/ADVISORIES ON TROPICAL STORM MELISSA ARE ISSUED UNDER WMO HEADER WTNT24 KNHC AND UNDER AWIPS HEADER MIATCMAT4. GALE-FORCE WINDS ARE EXPECTED TO AFFECT THE WESTERN AND CENTRAL AZORES BEGINNING LATE TODAY OR TONIGHT. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 37N TO 43N BETWEEN 35W AND 43W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT1/FZNT01 KWBC...FOR MORE DETAILS ABOUT THE WINDS AND SEA HEIGHTS THAT ACCOMPANY TROPICAL STORM MELISSA. A MIDDLE LEVEL TO UPPER LEVEL TROUGH CONTINUES IN THE CENTRAL ATLANTIC OCEAN TO THE SOUTH AND SOUTHWEST OF THE AREA OF TROPICAL STORM MELISSA. A SURFACE TROUGH IS ALONG 32N46W 27N46W 22N48W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE WITHIN 180 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 32N33W 25N40W 18N48W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES ACROSS COASTAL GUINEA NEAR 8N13W TO 7N16W 6N21W. THE ITCZ CONTINUES FROM 6N21W TO 5N27W 5N32W 3N42W AND 3N49W. A SURFACE TROUGH IS ALONG 5N44W 10N48W. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 2N TO 7N BETWEEN 22W AND 47W. SCATTERED MODERATE TO ISOLATED STRONG FROM 4N TO 6N BETWEEN 9W AND 16W...FROM 9N TO 10N BETWEEN AND 17W... FROM 6N TO 10N BETWEEN 47W AND 53W. ...DISCUSSION... THE GULF OF MEXICO... MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE GULF OF MEXICO. A MIDDLE LEVEL TO UPPER LEVEL CENTRAL ATLANTIC/EAST CENTRAL ATLANTIC OCEAN TROUGH SUPPORTS A COLD FRONT THAT CUTS THROUGH THE CENTRAL ATLANTIC OCEAN...THROUGH 32N52W TO 29N60W AND 28N65W. THE FRONT BECOMES STATIONARY FROM 28N65W ACROSS THE NORTHERN BAHAMAS...TO FLORIDA JUST TO THE SOUTH OF LAKE OKEECHOBEE...TO 25N87W IN THE SOUTHEASTERN GULF OF MEXICO. CONVECTIVE PRECIPITATION...BROKEN TO OVERCAST MULTILAYERED CLOUDS AND ISOLATED MODERATE ARE IN THE ATLANTIC OCEAN TO THE NORTH OF 32N44W 26N60W 25N70W 25N80W...AND IN THE GULF OF MEXICO TO THE NORTH OF 24N...AND IN THE SOUTHWESTERN CORNER OF THE AREA WITHIN A 30 NM RADIUS OF 19N93.5W. A SURFACE RIDGE PASSES THROUGH LOUISIANA INTO CENTRAL TEXAS. LOW CLOUD CEILINGS AND MIDDLE LEVEL CLOUD CEILINGS COVER THE TEXAS GULF COASTAL PLAINS...SOUTHERN COASTAL LOUISIANA. LOW CLOUD CEILINGS AND VISIBILITIES OF 3 MILES OR LESS WITH FOG AROUND LAKE PONTCHARTRAIN IN SOUTHEASTERN LOUISIANA. LOW CLOUD CEILINGS AND VISIBILITIES OF 3 MILES OR LESS ARE IN SOUTH CENTRAL COASTAL LOUISIANA. LOW CLOUD CEILINGS COVER THE FLORIDA PANHANDLE FROM CROSS CITY WESTWARD. MULTILAYERED CLOUD CEILINGS ARE OBSERVED IN THE TAMPA METROPOLITAN AREA...TO SARASOTA. ...HISPANIOLA... A WEAK MIDDLE LEVEL TO UPPER LEVEL TROUGH CUTS ACROSS CENTRAL SECTIONS OF HISPANIOLA. COMPARATIVELY DRIER AIR IN SUBSIDENCE...AS SEEN IN WATER VAPOR IMAGERY...COVERS THE AREA. THE GFS FORECAST FOR 250 MB SHOWS THAT NORTHWESTERLY WIND FLOW WILL PASS ON TOP OF HISPANIOLA DURING THE NEXT 48 HOURS...BEING ON THE NORTHEASTERN SIDE OF A RIDGE. THE GFS FORECAST FOR 500 MB SHOWS THAT NORTHERLY WIND FLOW WILL PASS ON TOP OF HISPANIOLA FOR THE NEXT 48 HOURS...WITH A WEST-TO-EAST ORIENTED RIDGE. THE GFS FORECAST FOR 700 MB SHOWS THAT HISPANIOLA WILL START WITH WEAK ANTICYCLONIC WIND FLOW FOR THE FIRST 12 HOURS OR SO...AND THEN CONTINUE FOR THE REST OF THE 48 HOUR FORECAST PERIOD WITH NORTHEASTERLY WINDS ACROSS THE AREA...IN A NORTHWEST-TO- SOUTHEAST ORIENTED RIDGE. THE REST OF THE CARIBBEAN SEA... A SURFACE TROUGH IS ALONG 79W/80W FROM 11N TO 18N MOVING WESTWARD ABOUT 10 KNOTS. CONVECTIVE PRECIPITATION...ISOLATED MODERATE FROM 11N TO 20N BETWEEN 76W AND 81W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO STRONG AROUND THE ISLANDS OF THE NORTHEASTERN CARIBBEAN SEA FROM 17N TO 19N BETWEEN 63W AND 66W. RAINSHOWERS ARE POSSIBLE ELSEWHERE FROM 12N TO 20N BETWEEN 61W AND 75W. ISOLATED MODERATE ALSO TO THE NORTH OF 16N TO THE WEST OF 80W IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA. MIDDLE LEVEL TO UPPER LEVEL CYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA TO THE EAST OF 74W. MIDDLE LEVEL EASTERLY WIND FLOW IS MOVING ACROSS THE TOP OF THE SAME AREA. MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA THAT IS TO THE WEST OF 74W. THE MONSOON TROUGH PASSES THROUGH 9N75W IN COLOMBIA...TO 9N80W IN PANAMA...BEYOND 8N84W IN SOUTHERN COSTA RICA...INTO THE EASTERN PACIFIC OCEAN. RAINSHOWERS ARE POSSIBLE TO THE SOUTH OF 11N TO THE WEST OF 76W. THE REST OF THE ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 15N23W JUST TO THE EAST OF THE CAPE VERDE ISLANDS. CYCLONIC WIND FLOW COVERS THE AREA FROM 3N TO 24N BETWEEN AFRICA AND 40W. COMPARATIVELY DRIER AIR IN SUBSIDENCE...AS SEEN IN WATER VAPOR IMAGERY...COVERS THE AREA FROM 6N TO 15N BETWEEN 20W AND 33W. A SURFACE RIDGE EXTENDS FROM A 1022 MB HIGH PRESSURE CENTER THAT IS NEAR 33N17W...TO A SECOND 1022 MB HIGH PRESSURE CENTER THAT IS NEAR 30N26W...TO 28N35W AND 18N38W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT1/FZNT01 KWBC...FOR MORE DETAILS ABOUT THE WINDS AND SEA HEIGHTS THAT ACCOMPANY TROPICAL STORM MELISSA. ONE AREA OF INTEREST CONSISTS OF SOUTH TO SOUTHWEST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS 8 TO 11 FEET TO THE NORTH OF 30N BETWEEN 36W AND 40W. A SECOND AREA OF INTEREST CONSISTS OF WINDS 20 KNOTS OR LESS AND SEA HEIGHTS 8 TO 12 FEET ELSEWHERE TO THE NORTH OF A LINE FROM 31N35W TO 24N46W TO 31N52W. A THIRD AREA OF INTEREST CONSISTS OF A COLD FRONT FROM 31N43W TO 28N65W THEN STATIONARY TO 26N80W. EXPECT NORTHEAST TO EAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS 8 TO 10 FEET TO THE NORTH THE FRONT TO THE WEST OF 60W. A FOURTH AREA OF INTEREST CONSISTS WINDS 20 KNOTS OR LESS AND SEA HEIGHTS 8 TO 9 FEET FROM 08N TO 17N TO THE EAST OF 46W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT