000 AXNT20 KNHC 010001 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUL 31 2011 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 2330 UTC. ...SPECIAL FEATURES... 1007 MB AREA OF LOW PRES IS APPROXIMATELY 500 MILES E OF THE LESSER ANTILLES NEAR 13.5N53W MOVING W-NW AROUND 10 KT. SCATTERED MODERATE TO STRONG CONVECTION IS POSITIONED WITHIN 90-120 NM OF THE LOW CENTER. SATELLITE IMAGERY INDICATES THAT THE LOW DOES NOT YET HAVE A WELL DEFINED SURFACE CIRCULATION. UNFORTUNATELY COMMUNICATIONS PROBLEMS HAVE LIMITED THE AMOUNT OF DATA RECEIVED FROM AN AIR FORCE RESERVE AIRCRAFT INVESTIGATING THE ELONGATED AREA OF LOW PRESSURE. THIS SYSTEM STILL HAS A HIGH LIKELIHOOD OF BECOMING A TROPICAL CYCLONE TONIGHT OR MONDAY AND IF IT DOES...TROPICAL STORM WATCHES OR WARNINGS WOULD BE ISSUED FOR PORTIONS OF THE NORTHERN WINDWARD ISLANDS AND THE LEEWARD ISLANDS ON VERY SHORT NOTICE. THUS...INTERESTS IN THESE AREAS SHOULD CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM. A TROPICAL WAVE HAS FRACTURED OFF FROM THE ABOVE MENTIONED AREA OF LOW PRES AND IS ALONG 59W FROM 12N TO 22N...APPROACHING THE LESSER ANTILLES WHILE MOVING W AROUND 15-20 KT. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120-150 NM AHEAD OF THE WAVE SPREADING OVER THE LESSER ANTILLES. THIS WAVE WILL CONTINUE TO BRING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO PORTIONS OF THE LESSER ANTILLES TONIGHT AND ON MON. ...TROPICAL WAVES... A TROPICAL WAVE IS IN THE CENTRAL TROPICAL ATLC ALONG 41W FROM 11N TO 21N MOVING W AROUND 15 KT. THIS WAVE IS LOCATED ALONG THE LEADING EDGE OF A WEAK LOW LEVEL MOISTURE SURGE DEPICTED ON TOTAL PRECIPITABLE WATER SATELLITE IMAGERY. WATER VAPOR SATELLITE IMAGERY INDICATES AN UPPER LEVEL INVERTED TROUGH IS IN THE VICINITY OF THE WAVE WHICH WILL INHIBIT ANY DEVELOPMENT OF THE WAVE. NO SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE. A TROPICAL WAVE EXTENDS FROM THE S CENTRAL GULF OF MEXICO TO ACROSS THE YUCATAN PENINSULA AND CENTRAL AMERICA S OF 23N ALONG 88W MOVING W AROUND 10 KT. ASSOCIATED SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 120-180 NM AHEAD OF THE WAVE BRINGING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO THE YUCATAN PORTION OF MEXICO...BELIZE AND GUATEMALA. ADDITIONAL HEAVY RAINFALL IS OCCURRING TO THE SE OF THE WAVE OVER HONDURAS... NICARAGUA AND THE NW CARIBBEAN BEING ENHANCED BY AN UPPER LEVEL LOW OVER THE NW CARIBBEAN. FLASH FLOODING WILL BE POSSIBLE OVER THOSE LAND AREAS DURING THE NEXT 24 HOURS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 21N17W TO 11N32W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N32W TO 07N45W TO 1007 MB LOW PRES NEAR 13.5N53W TO THE COAST OF VENEZUELA NEAR 10N62W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 180 NM N OF THE ITCZ BETWEEN 41W AND 45W AND WITHIN 180-240 NM S OF THE ITCZ BETWEEN 44W AND 48W. ...DISCUSSION... GULF OF MEXICO... A 1020 MB HIGH IS ALONG THE TEXAS COAST NEAR GALVESTON BAY AT 29N94.5W PRODUCING MAINLY FAIR WEATHER OVER THE NW GULF ASIDE FROM ISOLATED SHOWERS AND TSTMS. A WEAK SURFACE TROUGH IS IN THE SW GULF FROM 23N96W TO 19N94W PRODUCING SCATTERED SHOWERS AND TSTMS AHEAD OF IT MOVING INLAND OVER E MEXICO. ANOTHER WEAK SURFACE TROUGH EXTENDS FROM N FLORIDA TO THE GULF COAST NEAR 29N83W TO 27.5N85W PRODUCING SCATTERED SHOWERS AND TSTMS IN THE NE GULF WATERS. THE TROPICAL WAVE IN THE S CENTRAL GULF DESCRIBED ABOVE WILL PUSH INTO THE E BAY OF CAMPECHE AND SW GULF MON THROUGH TUE. OTHERWISE WEEK RIDGING WILL BE THE DOMINANT FEATURE OVER THE GULF THROUGH THE WEEK...RESULTING IN LIGHT TO MODERATE WINDS WITH SEAS OF 1-3 FT IN THE N GULF AND 2-4 FT IN THE S GULF. CARIBBEAN SEA... A TROPICAL WAVE IS OVER CENTRAL AMERICA PRODUCING CONVECTION OVER LAND AND ADJACENT WATERS IN THE NW CARIBBEAN AS DESCRIBED ABOVE. DIURNALLY DRIVEN AND OROGRAPHICALLY ENHANCED CONVECTION IS OVER CUBA AND ALONG ADJACENT COASTAL AREAS AS WELL AS ACROSS W JAMAICA. THIS ACTIVITY WILL DIMINISH DURING THE NEXT FEW HOURS WITH THE LOSS OF DAYTIME HEATING. ADDITIONAL CONVECTION IS ENTERING THE E CARIBBEAN ASSOCIATED WITH THE TROPICAL WAVE DESCRIBED IN THE SPECIAL FEATURES SECTION ABOVE. AGAIN... INTERESTS IN THE LESSER ANTILLES AND NE CARIBBEAN SHOULD CONTINUE TO MONITOR THIS WAVE AND A TRAILING AREA OF LOW PRES FOR POSSIBLE TROPICAL CYCLONE DEVELOPMENT TONIGHT OR ON MON. ATLANTIC OCEAN... 1028 MB HIGH PRES IS SW OF THE AZORES NEAR 27.5N33W WITH A RIDGE AXIS EXTENDING FROM THE HIGH TO 28N65W PRODUCING MAINLY FAIR WEATHER. THE CIMSS SAHARAN AIR LAYER TRACKING PRODUCT AND VISIBLE METEOSAT-9 SATELLITE IMAGERY SHOW A LARGE AREA OF AFRICAN DUST FROM 14N TO 32N E OF 40W. AN UPPER LEVEL LOW IS POSITIONED OVER 25N42W PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 23N TO 29N BETWEEN 35W AND 43W. ANOTHER UPPER LEVEL LOW IS OVER 27N55W PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 25N BETWEEN 55W AND 60W. OTHERWISE...THE ABOVE DESCRIBED ATLC TROPICAL WAVES AND AREA OF LOW PRES E OF THE LESSER ANTILLES ARE THE PREDOMINATE WEATHER PRODUCERS IN THE ATLC BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LEWITSKY