000 AXNT20 KNHC 190003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST MON NOV 18 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 FEATURE... SUBTROPICAL STORM MELISSA IS LOCATED NEAR 29.8N 54.2W OR ABOUT 564 NM ESE OF BERMUDA AT 18/2100 UTC. THIS SYSTEM IS MOVING NW AT 8 KT WITH MAXIMUM SUSTAINED WINDS OF 50 KT AND HIGHER GUSTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB. SCATTERED MODERATE CONVECTION AND TSTMS ASSOCIATED TO THIS SYSTEM ARE N OF 14N BETWEEN 42W-52W AND N OF 26N BETWEEN 52W-56W. PLEASE SEE LATEST PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT4/WTNT34 KNHC AND THE FULL FORECAST ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE EAST TROPICAL ATLC NEAR 07N12W AND CONTINUES TO 05N16W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 05N27W TO 06N37W. WIDELY SCATTERED SHOWERS ARE FROM 04N-10N BETWEEN 14W-23W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 08N-12N BETWEEN 33W-44W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM THE GREAT LAKES TO NORTHERN FLORIDA AND SUPPORTS A FRONTAL SYSTEM ANALYZED AS A COLD FRONT FROM PANAMA CITY FLORIDA SW TO 28N92W TO SOUTHERN TEXAS NEAR 28N96W. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM NW FLORIDA NEAR 29N82W TO 27N90W TO THE WESTERN GULF NEAR 25N96W. RADAR IMAGERY SHOW HEAVY SHOWERS AND TSTMS WITHIN 60 NM SOUTH OF THE TROUGH AXIS E OF 85W...INCLUDING THE COASTAL WATERS FROM APALACHEE BAY TO CRYSTAL RIVER. SCATTERED SHOWERS ARE WITHIN 100 NM OF THE NORTHERN GULF COASTLINE BETWEEN 85W-96W. A MIDDLE TO UPPER LEVEL RIDGE CENTERED ON THE S-SE BASIN SUPPORTS A 1015 MB HIGH IN THE WESTERN-CENTRAL GULF NEAR 24N90W. WATER VAPOR IMAGERY DEPICT DRY AIR SUBSIDENCE FROM THE MIDDLE-UPPER LEVELS...THUS SUPPORTING FAIR WEATHER IN THE REMAINDER BASIN. THE COLD FRONT IS FORECAST TO EXTEND FROM CENTRAL FLORIDA SW TO NE MEXICO TUE AFTERNOON. BY WED AFTERNOON THE COLD FRONT IS EXPECTED TO TRANSITION INTO A STATIONARY FRONT FROM SW FLORIDA WESTWARD TO THE CENTRAL GULF. CARIBBEAN SEA... EXCEPT FOR THE CENTRAL-EASTERN CARIBBEAN...A MIDDLE TO UPPER LEVEL RIDGE DOMINATES THE BASIN WITH DRY AIR SUBSIDENCE SUPPORTING FAIR WEATHER. AN UPPER-LEVEL TROUGH OVER THE CENTRAL ATLC EXTENDS AN AXIS SW TO THE CENTRAL-EASTERN CARIBBEAN. MIDDLE- LEVEL DIFFLUENCE FROM THESE TWO FEATURES ALOFT AND LOW-LEVEL MOISTURE CONVERGENCE OVER THE CENTRAL BASIN SUPPORT SCATTERED SHOWERS S OF HISPANIOLA FROM 13N-18N BETWEEN 70W-76W. ANOTHER AREA OF MIDDLE-LEVEL DIFFLUENCE IS SUPPORTING SCATTERED SHOWERS IN THE WESTERN BASIN FROM 16N-19N BETWEEN 82W-86W. NE TO E TRADE WINDS ARE BANKING ISOLATED SHOWERS WITHIN 80 NM ALONG THE COAST OF PANAMA BETWEEN 79W-82W. GENTLE TO MODERATE E-NE TRADE WINDS WILL PREVAIL ACROSS MOST OF THE REGION THROUGH WED. A LOW PRESSURE CENTER IS FORECAST TO DEVELOP IN THE SW BASIN TUE AFTERNOON AND PREVAIL THROUGH WED NIGHT. ...HISPANIOLA... DRY STABLE AIR ALOFT CONTINUES ACROSS THE ISLAND TO SUPPORT FAIR WEATHER. HOWEVER...NE SURFACE FLOW MAY ENHANCE ISOLATED SHOWERS ACROSS THE MOUNTAINOUS REGIONS OF THE ISLAND. THE MIDDLE TO UPPER LEVEL TROUGH SUPPORTING THE SYSTEM IN THE SPECIAL FEATURE SECTION IS FORECAST TO EXTEND AN AXIS ACROSS THE ISLAND TO SUPPORT SHOWERS DURING THE DAY ON TUESDAY. ATLANTIC OCEAN... AN UPPER TROUGH COVERS THE CENTRAL ATLC BETWEEN 46W-67W AND SUPPORTS SUBTROPICAL STORM MELISSA. SEE THE SPECIAL FEATURE SECTION ABOVE FOR MORE DETAILS. IN THE SW NORTH ATLC...SCATTERED SHOWERS ARE N OF 28N W OF 75W PRECEDING A COLD FRONT THAT IS EXPECTED TO MOVE INTO THIS AREA EARLY TUE. A SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A 1030 MB HIGH OVER THE AZORES ISLANDS. A SURFACE RIDGE IS FORECAST BEHIND THE FRONT TUE THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR