000 AXNT20 KNHC 251206 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT AUG 25 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1145 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM ISAAC AT 25/1200 UTC WAS LOCATED NEAR 19.7N 73.8W. THIS POSITION IS ABOUT 150 KM ESE OF GUANTANAMO CUBA. ISAAC IS MOVING NW AT 12 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. A 1006 MB LOW AND ASSOCIATED TROPICAL WAVE AXIS IS LOCATED SW OF THE CAPE VERDE ISLANDS NEAR 13N28W MOVING WNW AT ABOUT 12 KT. THIS FEATURE IS EMBEDDED IN THE BROAD SCALE MONSOON GYRE ON SATELLITE IMAGERY...WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT ACROSS MUCH OF THE EASTERN TROPICAL ATLC. A THICK LAYER OF SAHARAN DUST SURROUNDS THE WAVE AND ASSOCIATED LOW... INHIBITING THIS SYSTEM TO GENERATE CONVECTION NEAR THE CENTER. THEREFORE...THE SYSTEM REMAINS FAIRLY DISORGANIZED WITH THE MAJORITY OF THE CONVECTION TO THE WEST AND WELL TO THE SW OF THE LOW CENTER. SCATTERED MODERATE CONVECTION IS FROM 11N-17N BETWEEN 27W-32W...AND FORM 7N-10N BETWEEN 32W-42W. ENVIRONMENTAL CONDITIONS ARE MARGINALLY CONDUCIVE FOR DEVELOPMENT. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS WEST AFRICA...ENTERING THE ERN TROPICAL ATLC OVER THE COAST OF MAURITANIA AT 20N16W CONTINUING WSW TO THE SPECIAL FEATURE 1006 MB LOW AND ASSOCIATED TROPICAL WAVE AT 13N28W AND ALONG 8N35W TO 9N44W...WHERE THE ITCZ CONTINUES ALONG 12N53W TO NEAR THE COAST OF VENEZUELA AT 11N63W. WHILE NO CONVECTION IS NOTED AROUND THE ITCZ...THE CONVECTION NEAR THE MONSOON TROUGH IS DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL NORTHERLY FLOW COVERS MOST OF THE BASIN...BEHIND THE BASE OF AN UPPER TROUGH THAT MOVES ACROSS THE FAR ERN REGION OF THE GULF. THIS FEATURE IS PROVIDING SOME WEAK TO MODERATE DIFFLUENCE ALOFT OVER THE N-CENTRAL BASIN...GENERATING AN AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 26N BETWEEN 87W-95W. DRY AIR AND STRONG SUBSIDENCE IS SINKING ACROSS THE ERN BASIN PROVIDING FAIR CONDITIONS E OF 87W. HOWEVER...LOW LEVEL MOISTURE AND STRONG CONVECTION IS BEING BROUGHT FROM THE EAST ACROSS THE STRAITS OF FLORIDA DUE TO THE LARGE CYCLONIC WIND FIELD OF TROPICAL STORM ISAAC. SOME OF THIS ACTIVITY HAS ENTERED THE AREA THIS MORNING NOTED ON DOPPLER RADAR AS A FEW SQUALL LINES S OF 25N E OF 83W. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO REMAIN OVER THE NW GULF. SIMILAR CONVECTION WILL ALSO CONTINUE ACROSS THE SE GULF AS TROPICAL STORM ISAAC MOVES CLOSER. WINDS WILL ALSO BEGIN TO INCREASE OVER THE SE GULF THROUGHOUT THE WEEKEND. ALL INTERESTS IN THE EASTERN GULF SHOULD MONITOR THE PROGRESS OF ISAAC. CARIBBEAN SEA... TROPICAL STORM ISAAC CONTINUES TO BE THE MAIN WEATHER CONCERN IN THE CARIBBEAN SEA...GENERATING CONSIDERABLE CONVECTION OVER THE CENTRAL AND ERN BASIN. ALL INTERESTS IN THE NORTHERN CARIBBEAN SHOULD MONITOR THE PROGRESS ON ISAAC. FLOODING AND MUDSLIDES ARE DEFINITE HAZARDS ACROSS THE ISLANDS IMPACTED. THE W AND SW CARIBBEAN BASINS ARE STILL UNDER FAIR CONDITIONS DUE TO TO DRY AIR ALOFT COVERING MUCH OF THE AREA WEST OF 80W. THE LARGE CIRCULATION OF ISAAC IS PROVIDING CYCLONIC SURFACE FLOW ACROSS THE ENTIRE BASIN WITH LIGHT WINDS ONLY ACROSS THE SW CARIBBEAN. SOME STRONG SHOWERS AND THUNDERSTORMS HAVE ALSO RECENTLY POPPED UP OVER MUCH OF PANAMA AND NRN COLOMBIA...LIKELY INFLUENCED BY THE ERN PACIFIC MONSOON TROUGH. ISAAC WILL CONTINUE TO DOMINATE THE WEATHER PATTERN ACROSS THE CARIBBEAN AS IT CONTINUES TO MOVE NW ACROSS THE WINDWARD PASSAGE AND THEN ERN CUBA BEFORE HEADING INTO THE FLORIDA STRAITS. ATLANTIC OCEAN... THE COMBINATION OF LOW-LEVEL MOISTURE BEING DRAWN ACROSS THE NW BAHAMAS DUE TO TROPICAL STORM ISAAC AND DIFFLUENCE ALOFT AROUND AN UPPER TROUGH OVER THE EASTERN GULF IS HELPING PRODUCE SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE BAHAMAS AND STRAITS OF FLORIDA S OF 28N W OF 71W. THE OUTER CONVECTION BANDS ASSOCIATED TO ISAAC ARE ALSO AFFECTING THE NRN COASTAL WATERS OF HISPANIOLA...ERN CUBA...AND TURKS AND CAICOS. TO THE ENE OF THESE AREAS OF CONVECTION...A WEAK SURFACE TROUGH IS ANALYZED ALONG 31N62W TO 26N63W WITH MINIMAL ACTIVITY IN THE WRN VICINITY OF ITS AXIS. AN ELONGATED UPPER LEVEL LOW IS CENTERED NEAR 25N57W. THIS FEATURE HAS TAKEN OVER THE REMNANTS OF FORMER TROPICAL STORM JOYCE...NOW ANALYZED AS A SURFACE TROUGH FROM 25N52W TO 18N50W. SCATTERED SHOWERS AND THUNDERSTORMS ARE FROM 22N-29N BETWEEN 51W-56W. THE REMAINDER OF THE ATLC BASIN DISCUSSION AREA IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1023 MB HIGH NEAR 34N45W AND A 1022 MB HIGH NEAR 33N35W. THE FAIR WEATHER IS ENHANCED ALOFT BY SAHARAN DUST NOTED ON METEOSAT-9 IMAGERY. EMBEDDED IN THIS DRY ENVIRONMENT...AN UPPER LOW WOBBLES NEAR 31N22W. EXPECT WEATHER CONDITIONS TO DETERIORATE OVER THE NRN COASTAL WATERS OF HISPANIOLA...TURKS AND CAICOS...AND THE BAHAMAS DURING THE NEXT FEW DAYS AS TROPICAL STORM ISAAC MOVES OVER HAITI AND CUBA BEFORE HEADING INTO THE FLORIDA STRAITS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA