000 AXNT20 KNHC 242351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI AUG 24 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 2315 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM ISAAC AT 24/0000 UTC IS NEAR 17.3N 72.0W. THIS POSITION IS ABOUT 80 NM SSE OF PORT AU PRINCE HAITI...OR ABOUT 235 NM SE OF GUANTANAMO CUBA. ISAAC IS MOVING NW AT 9 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. A LARGE RAINBAND ON THE EAST SIDE OF ISAAC IS PRODUCING A LARGE AREA OF STRONG CONVECTION FROM 14N-18N BETWEEN 67W-69W. NUMEROUS MODERATE CONVECTION IS ELSEWHERE FROM 12N-20N BETWEEN 66W-75W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO IMPACTING THE BAHAMAS AND SOUTH FLORIDA. ALTHOUGH THIS AREA OF CONVECTION IS REMOVED FROM THE MAIN RAINBANDS AROUND ISAAC...THE WIDE CYCLONIC CIRCULATION OF ISAAC DOES EXTEND ACROSS THESE AREAS AND IS CONTRIBUTING TO THE ACTIVITY. AN UPPER LEVEL TROUGH OVER THE EASTERN GULF OF MEXICO IS ALSO PROVIDING DIFFLUENCE ALOFT OVER SE FLORIDA AND THE BAHAMAS...WHICH IS FURTHER CONTRIBUTING TO THE DEVELOPMENT OF STRONG CONVECTION. A TROPICAL WAVE EXTENDS FROM 20N20W ACROSS THE CAPE VERDE ISLANDS TO A 1007 MB SURFACE LOW NEAR 14N25W MOVING WNW NEAR 12 KT. THE WAVE/LOW LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT ACROSS MUCH OF THE EASTERN TROPICAL ATLC. THE SYSTEM IS FAIRLY DISORGANIZED WITH THE MAJORITY OF THE CONVECTION WELL TO THE WEST OF THE LOW CENTER. CURRENTLY SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-11N BETWEEN 27W-35W...WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 13N-16N BETWEEN 26W-30W. ENVIRONMENTAL CONDITIONS ARE SOMEWHAT CONDUCIVE FOR FURTHER DEVELOPMENT OF THE SYSTEM OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... A TROPICAL WAVE IS IN THE VICINITY OF THE CAPE VERDE ISLANDS. SEE SPECIAL FEATURES SECTION ABOVE. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 18N16W CONTINUING TO A 1007 MB SURFACE LOW CONNECTED TO A TROPICAL WAVE AT 13N25W AND ALONG 11N31W 13N41W. THE ITCZ BEGINS AT 10N50W TO 8N59W. NO DEEP CONVECTION IS NEAR THE MONSOON TROUGH/ITCZ AXIS EXCEPT FOR CONVECTION ALREADY DISCUSSED WITH THE TROPICAL WAVE IN THE SPECIAL FEATURES SECTION. ...DISCUSSION... THE GULF OF MEXICO... WEAK SURFACE RIDGING REMAINS OVER THE GULF OF MEXICO EXTENDING FROM THE NE CONUS. HOWEVER...AN UPPER LEVEL TROUGH COVERS THE BASIN EXTENDING FROM SOUTH CAROLINA TO WESTERN CUBA. DRY AIR IS SINKING ACROSS THE NE CORNER OF THE BASIN PROVIDING FAIR CONDITIONS...BUT SOUTH FLORIDA LIES IN THE DIFFLUENT SIDE OF THE UPPER TROUGH...WHICH IS HELPING ENHANCE SHOWERS/THUNDERSTORMS...SOME WHICH ARE SEVERE. LOW-LEVEL MOISTURE IS BEING BROUGHT FROM THE EAST ACROSS THIS AREA DUE TO THE LARGE CYCLONIC CIRCULATION OF TROPICAL STORM ISAAC SOUTH OF HISPANIOLA. STRONG SHOWERS/THUNDERSTORMS ARE ALSO OVER THE YUCATAN PENINSULA. A SHORTWAVE UPPER TROUGH IS OVER THE FAR WESTERN GULF...WHICH IS HELPING SUPPORT SHOWERS/THUNDERSTORMS IN THE NW GULF N OF 25N BETWEEN 90W-96W. SHOWERS/THUNDERSTORMS ARE EXPECTED TO REMAIN OVER THE NW GULF. SHOWERS/THUNDERSTORMS 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. THE CARIBBEAN SEA... TROPICAL STORM ISAAC IS DOMINATING THE CENTRAL CARIBBEAN PRODUCING WIDESPREAD SHOWERS/THUNDERSTORMS FROM VENEZUELA TO HISPANIOLA AND CUBA. ALL INTERESTS IN THE NORTHERN CARIBBEAN SHOULD MONITOR THE PROGRESS ON ISAAC. FLOODING AND MUDSLIDES ARE POSSIBLE ACROSS THE ISLANDS IMPACTED. THE WESTERN CARIBBEAN IS STILL UNDER FAIR CONDITIONS DUE TO TO DRY AIR ALOFT COVERING MUCH OF THE AREA WEST OF 77W. 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/THUNDERSTORMS HAVE ALSO RECENTLY POPPED UP OVER MUCH OF PANAMA. THIS IS LIKELY INFLUENCED BY THE E PACIFIC MONSOON TROUGH. TROPICAL STORM ISAAC WILL CONTINUE TO DOMINATE THE WEATHER PATTERN ACROSS THE CARIBBEAN AS IT CONTINUES TO MOVE NW ACROSS HAITI AND THEN CUBA BEFORE HEADING INTO THE FLORIDA STRAITS. THE ATLANTIC OCEAN... THE COMBINATION OF LOW-LEVEL MOISTURE BEING DRAWN ACROSS THE BAHAMAS DUE TO TROPICAL STORM ISAAC AND DIFFLUENCE ALOFT AROUND AN UPPER TROUGH OVER THE EASTERN GULF IS HELPING PRODUCE SCATTERED SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE BAHAMAS AND SOUTH FLORIDA S OF 28N W OF 70W. UPPER LEVEL RIDGING...OUTFLOW FROM ISAAC COVERS THE MAJORITY OF THE WEST ATLC PROVIDING WEAK SURFACE RIDGING N OF THE CIRCULATION OF ISAAC. AN UPPER LEVEL LOW IS TO THE EAST NEAR 23N55W. IT IS HELPING PRODUCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 29N BETWEEN 60W-62W...ISOLATED SHOWERS/THUNDERSTORMS FROM 22N-30N BETWEEN 50W-58W...AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 20N-23N BETWEEN 46W-49W. THIS LAST AREA OF ACTIVITY IS ASSOCIATED WITH THE REMNANTS OF T.D. JOYCE CURRENTLY CENTERED NEAR 18N47W. THE LOW CENTER HAS MOSTLY DISSIPATED AND WILL LIKELY BE DROPPED FROM THE ANALYSIS AT 0000 UTC. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1022 MB SURFACE HIGH AT 33N42W. THE HIGH IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 33N36W. A NARROW UPPER TROUGH IS TO THE E EXTENDING FROM THE MADEIRA ISLANDS TO W OF THE CAPE VERDE ISLANDS...BUT IS NOT CAUSING ANY ACTIVE WEATHER IN THE DISCUSSION AREA. THE LAST VISIBLE SATELLITE IMAGES OF THE DAY INDICATE A LARGE AREA OF DUST EXTENDS AROUND THE TROPICAL WAVE IN THE EAST TROPICAL ATLC AND AROUND THE REMNANTS OF T.D. JOYCE. A FEW STATIONS IN THE EASTERN CARIBBEAN ARE ALSO REPORTING DUST. THE DUST IS HELPING CONTRIBUTE TO FAIR CONDITIONS ACROSS MUCH OF THE ATLC BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON