000 AXNT20 KNHC 272356 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON AUG 27 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 28/0000 UTC IS NEAR 26.7N 86.5W. THIS POSITION IS ABOUT 200 NM SE OF THE MOUTH OF THE MISSISSIPPI RIVER...AND ABOUT 255 NM SSE OF MOBILE ALABAMA. ISAAC IS MOVING NW AT 9 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 981 MB. THE MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 KT. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS NEAR THE CENTER AND TO THE WEST FROM 25N-28N BETWEEN 85W-90W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 24N-30N BETWEEN 83W-91W. EVEN THOUGH ISAAC IS MOVING AWAY FROM THE FLORIDA PENINSULA...A LARGE AREA OF SHOWERS/THUNDERSTORMS IS STILL IMPACTING THE STATE. RADAR IMAGERY INDICATES A SWATH OF HEAVY SHOWERS/ISOLATED THUNDERSTORMS IS ALONG THE EASTERN FLORIDA COAST EXTENDING OFFSHORE TO 79W AND CONTINUING FARTHER OFF THE NE COAST OF FLORIDA TO 77W. A 1011 MB SURFACE LOW IS CENTERED NEAR 21N42W IN THE CENTRAL TROPICAL ATLC. THE LOW HAS BEEN MOVING NW AT ABOUT 15 KT. THE SYSTEM IS CURRENTLY SHEARED WITH CONVECTION EXTENDING NE OF THE LOW CENTER WHERE A CLUSTER OF STRONG CONVECTION IS FROM 23N-26N BETWEEN 38W-42W. FURTHER DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 22N21W TO A 1011 MB SURFACE LOW AT 11N22W MOVING W NEAR 12 KT. THE WAVE/LOW COINCIDES WITH A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. BROAD LOW-LEVEL CYCLONIC FLOW IS ALSO ABOUT THE WAVE AND LOW...BUT IS NOT WELL ORGANIZED. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-12N BETWEEN 23W-32W. A CLUSTER OF SCATTERED STRONG CONVECTION IS ALSO MOVING OFF THE COAST OF AFRICA BEHIND THE WAVE FROM 11N-15N BETWEEN 13W-18W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 15N17W CONTINUING TO A SURFACE LOW EMBEDDED WITHIN THE MONSOON TROUGH AND ATTACHED TO A TROPICAL WAVE AT 11N22W. THE MONSOON TROUGH BEGINS AGAIN SOUTH OF A SURFACE LOW IN THE CENTRAL ATLC ALONG 16N42W 13N46W 10N54W. THE ITCZ CONTINUES FROM 10N54W TO 8N61W. SCATTERED MODERATE CONVECTION IS FROM 10N-15N BETWEEN 52W-57W. ...DISCUSSION... THE GULF OF MEXICO... TROPICAL STORM ISAAC CONTINUES TO IMPACT THE GULF OF MEXICO AS IT MOVES INTO THE NORTH CENTRAL GULF. THE STRONGEST CONVECTION IS NEAR THE CENTER AND TO THE WEST WITH SOME LIGHTER SHOWERS ALREADY MOVING INTO THE FLORIDA PANHANDLE AND SOUTHERN ALABAMA. AN OUTER RAINBAND...WHICH HAS NOW MOSTLY CUT OFF FROM THE STORM...CONTINUES TO IMPACT EASTERN FLORIDA. ISOLATED TORNADOES HAVE ALSO POPPED UP THROUGHOUT THE FLORIDA PENINSULA THROUGHOUT THE DAY AND THE RISK IS STILL PRESENT. THE CYCLONIC CIRCULATION OF ISAAC COVERS THE ENTIRE BASIN...BUT WINDS ACROSS THE WESTERN GULF ARE STILL LIGHT AT THIS TIME WITH MOSTLY CLEAR SKIES. THE FAIR WEATHER CAN BE ATTRIBUTED TO DRY AIR ALOFT WRAPPING AROUND AN UPPER LEVEL LOW CENTERED IN THE WESTERN GULF NEAR 23N92W. STORMY CONDITIONS WILL REMAIN ACROSS A LARGE PORTION OF THE GULF FOR THE NEXT SEVERAL DAYS. INTERESTS IN THE ENTIRE GULF COAST SHOULD MONITOR THE PROGRESS OF ISAAC. THE CARIBBEAN SEA... SOME STRONG WINDS UP TO 25 KT ARE STILL ACROSS THE NW CARIBBEAN NEAR AN AREA OF SHOWERS/THUNDERSTORMS N OF 20N BETWEEN 79W-82W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS EASTERN CUBA AND PORTIONS OF HISPANIOLA. DEEP LAYER MOISTURE REMAINS ACROSS MUCH OF THE BASIN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY...BUT DRY AIR ALOFT IS HELPING PROVIDE FAIR CONDITIONS ACROSS THE MAJORITY OF THE WESTERN CARIBBEAN. AN ELONGATED UPPER LEVEL LOW/TROUGH EXTENDS FROM HISPANIOLA TO NORTHERN COLOMBIA...WHICH IS PROVIDING MOIST DIFFLUENCE ALOFT OVER THE EASTERN CARIBBEAN. THIS IS HELPING SUPPORT SOME CLUSTERS OF STRONG CONVECTION ACROSS NORTHERN VENEZUELA WITH SOME ISOLATED SHOWERS ACROSS THE REMAINDER OF THE EASTERN CARIBBEAN. STRONG TRADEWIND FLOW OF MOSTLY 20 KT IS ACROSS MUCH OF THE CENTRAL AND EASTERN PORTIONS OF THE BASIN WITH SOME STRONGER WINDS N OF VENEZUELA AND COLOMBIA. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... WIDESPREAD SHOWERS/THUNDERSTORMS EXTEND ALONG THE ENTIRE FLORIDA EAST COAST AND CONTINUE FARTHER EAST N OF THE BAHAMAS OUT TO 77W. THIS ACTIVITY BEGAN AS AN OUTER BAND OF ISAAC...BUT HAS NOW SEPARATED FROM THE MAIN CONVECTIVE PATTERN OF THE STORM...AS INDICATED IN RADAR IMAGERY. THE REMAINDER OF THE WEST ATLC IS MOSTLY DRY EXCEPT FOR SOME SHOWERS N OF THE EASTERN CARIBBEAN FROM 19N-22N BETWEEN 65W-68W. THIS ACTIVITY IS ENHANCED BY DIFFLUENCE ALOFT AROUND THE EAST SIDE OF AN UPPER LEVEL TROUGH EXTENDING ACROSS HISPANIOLA TO NORTHERN COLOMBIA. FARTHER E...A BROAD UPPER LEVEL RIDGE COVERS THE TROPICAL ATLC CENTERED NEAR 23N33W...EAST OF A SURFACE LOW THAT IS PRODUCING SOME SHOWERS/THUNDERSTORMS. THE UPPER RIDGE SUPPORTS A PAIR OF SURFACE HIGH CENTERS. ONE IS NEAR 32N49W PROVIDING SURFACE RIDGING ACROSS THE CENTRAL ATLC. THE SECOND IS CENTERED NEAR THE AZORES ISLANDS PROVIDING SURFACE RIDGING ACROSS THE FAR EASTERN ATLC. GOES-R ENHANCED SATELLITE IMAGERY CONTINUES TO SHOW THAT AN AREA OF DUST EXTENDS AROUND THE TROPICAL WAVE IN THE EAST ATLC TO THE SURFACE LOW IN THE CENTRAL ATLC. AN AREA OF DUST IS ALSO WEST OF THE LOW IN THE CENTRAL ATLC AND IS APPROACHING THE NE CARIBBEAN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON