000 AXNT20 KNHC 032355 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI AUG 03 2012 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 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM ERNESTO WAS CENTERED NEAR 13.9N 64.1W AT 03/2100Z OR ABOUT 210 MI...335 KM W OF ST. LUCIA AND 340 MI...545 KM SSE OF SAN JUAN PUERTO RICO MOVING W AT 18 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS COVER THE ERN CARIBBEAN E OF 67W TO OVER THE LESSER ANTILLES S OF 18N W OF 59W. A 1006 MB LOW PRESSURE SYSTEM IS LOCATED IN THE ERN ATLC NEAR 13N26W. THIS SYSTEM IS EMBEDDED IN A TROPICAL WAVE EXTENDING FROM 18N24W TO THE LOW LEVEL CENTER...FOUND WITHIN A BROAD REGION OF DEEP MOISTURE ASSOCIATED WITH THE MONSOONAL GYRE DESCRIBED BELOW. CLUSTERS OF MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE FROM 7N-14N BETWEEN 24W-31W. THE OVERALL ACTIVITY HAS BECOME MORE ORGANIZED AROUND THE LOW TODAY...AND IF CURRENT TRENDS CONTINUE...ADVISORIES COULD BE INITIATED LATER THIS EVENING. ALTHOUGH ENVIRONMENTAL CONDITIONS ARE CURRENTLY CONDUCIVE FOR TROPICAL CYCLONE FORMATION...DRY AIR AND COOLER WATERS COULD INHIBIT FURTHER DEVELOPMENT IN A DAY OR TWO. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES WEST-NORTHWESTWARD AT ABOUT 13 KT. ...TROPICAL WAVES... TROPICAL WAVE MOVES ACROSS THE CENTRAL TROPICAL ATLC...ANALYZED FROM 14N39W TO THE MONSOON TROUGH AXIS NEAR 7N41W MOVING W NEAR 10 KT. WAVE IS ALONG THE LEADING EDGE OF A SURGE OF DEEP MOISTURE DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. DRY AIR AND SAHARAN DUST ALOFT SURROUND THIS WAVE ALLOWING FOR ONLY SCATTERED WEAK CONVECTION WITHIN 120 NM ON EITHER SIDE OF THE WAVE AXIS. TROPICAL WAVE PREVIOUSLY MOVING ACROSS THE YUCATAN PENINSULA AND CENTRAL AMERICA IS NOW OVER ERN PACIFIC WATERS. FOR MORE INFORMATION ON THIS WAVE SEE EAST PACIFIC TROPICAL WEATHER DISCUSSION UNDER WMO HEADER AXPZ20 KNHC 032113 TWDEP. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS INLAND PORTIONS OF WEST AFRICA ENTERING THE ERN TROPICAL ATLC ALONG THE COAST OF MAURITANIA NEAR 21N17W CONTINUING WSW ALONG THE SPECIAL FEATURE LOW NEAR 13N26W TO JUST S OF CENTRAL ATLC TROPICAL WAVE NEAR 7N41W TO 6N46W...WHERE THE ITCZ AXIS CONTINUES TO 8N58W. SCATTERED WEAK TO MODERATE CONVECTION IS WITHIN 40 NM ON EITHER SIDE OF THE MONSOON TROUGH AND ITCZ E OF 50W. CLUSTERS OF MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE FROM 7N-14N BETWEEN 24W-31W... ASSOCIATED TO THE SPECIAL FEATURE LOW EMBEDDED IN THE MONSOONAL GYRE. ...DISCUSSION... GULF OF MEXICO... NE FLOW ALOFT CONTINUES TO DOMINATE THE UPPER LEVELS OF THE ATMOSPHERE ACROSS THE DISCUSSION AREA...AROUND THE BROAD OMEGA UPPER RIDGE ANCHORED OVER CENTRAL TEXAS. THIS UPPER LEVEL FLOW IS PUSHING SOME WEAK MID LEVEL ENERGY TO THE SRN CONUS STATES PROVIDING SOME ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS N OF 24N E BETWEEN 84W-90W. THE REMAINDER OF THE GULF IS DOMINATED BY SUBSIDENT DRY AIR ALOFT ASSOCIATED WITH THE UPPER RIDGE. THIS IS KEEPING FAIR WEATHER CONDITIONS ELSEWHERE ACROSS THE AREA. MODERATE CONVECTION WILL BEGIN TO ENTER THE FAR ERN GULF...AS A VIGOROUS SURFACE TROUGH CURRENTLY OVER THE NW BAHAMAS DRIFTS WNW OVER FLORIDA DURING THE NEXT 24-48 HOURS. CARIBBEAN SEA... A BROAD AREA OF SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS IS NOTED ON SATELLITE IMAGERY MOVING ACROSS THE ERN CARIBBEAN E OF 67W...ASSOCIATED TO TROPICAL STORM ERNESTO. THIS SYSTEM WILL CONTINUE TO SPREAD STRONG CONVECTION ACROSS THE ERN AND CENTRAL CARIBBEAN DURING THE NEXT 24 HOURS. SIMILAR ACTIVITY IS MORE SPREAD OVER THE FAR SW BASIN S OF 11N W OF 75W...RELATED TO THE MONSOON TROUGH EXTENDING FROM NRN COLOMBIA TO COSTA RICA. THE ACTIVITY ON THIS REGION IS EXPECTED TO LINGER DURING THE NEXT 24 HOURS. THE BASE OF A NARROW UPPER LEVEL TROUGH EXTENDS ACROSS THE NW CARIBBEAN SUPPORTING A FEW ISOLATED SHOWERS W OF 80W N OF 14N. OTHERWISE...DRY AIR ALOFT COVERS THE REMAINDER OF THE CARIBBEAN SUPPRESSING DEEP CONVECTION ELSEWHERE ACROSS THE AREA. ATLANTIC OCEAN... A NARROW UPPER TROUGH CONTINUES TO HOLD ITS PLACE OVER THE FAR WRN ATLC...SUPPORTING A SLOW MOVING 1013 MB LOW EMBEDDED IN A SURFACE TROUGH ANALYZED FROM 31N76W ACROSS THE NW BAHAMAS TO THE LOW LEVEL CENTER NEAR 25N79W ENDING NEAR THE COAST OF CUBA NEAR 23N80W. THIS SYSTEM IS GENERATING A BROAD AREA OF SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS S OF 32N W OF 72W TO ACROSS OVER THE FLORIDA PENINSULA. SHORT RANGE COMPUTER MODELS SUGGEST THIS SYSTEM WILL CONTINUE TO SLOWLY DRIFT WNW OVER THE NEXT 24 HOURS WITH CONTINUOUS CONVECTION AFFECTING THE COASTAL WATERS OF FLORIDA AND NW BAHAMAS. DUE TO THE SLOW MOVEMENT OF THIS SYSTEM...SOME LOCAL COASTAL AND INLAND FLOODING IS LIKELY OVER FLORIDA AND THE NW BAHAMAS DURING THE FORECAST PERIOD. A SECOND BUT MUCH WEAKER SURFACE TROUGH IS ANALYZED FROM 30N56W TO 25N61W...GENERATING SCATTERED SHOWERS WITHIN 120 NM E OF THE TROUGH AXIS. OTHERWISE...BROAD SURFACE RIDGING DOMINATES THE REMAINDER OF THE ATLC BASIN. METEOSAT-9 SATELLITE IMAGERY CONTINUES TO SHOW SAHARAN DUST COVERING MOST OF THE ATLC BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA