000 AXNT20 KNHC 270003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 26 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 27/0000 UTC IS NEAR 24.1N 82.6W. THIS POSITION IS ABOUT 50 NM SW OF KEY WEST FLORIDA...AND ABOUT 460 NM SE OF THE MOUTH OF THE MISSISSIPPI RIVER. ISAAC IS MOVING WNW AT 13 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 991 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. ISAAC IS PRODUCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION ACROSS A GOOD PORTION OF FLORIDA FROM 25N-30N BETWEEN 76W-84W. SIMILAR ACTIVITY IS SE OF THE STORM CENTER ACROSS CUBA FROM 19N-23N BETWEEN 77W-80W. SOME LARGER CLUSTERS OF STRONG CONVECTION HAVE POPPED UP WEST OF THE CENTER FROM 24N-26N BETWEEN 82W-84W. TROPICAL WAVE EXTENDS FROM 26N34W TO A 1009 MB SURFACE LOW NEAR 18N37W MOVING NW AT 10-15 KT. THE WAVE/LOW LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT ACROSS MUCH OF THE CENTRAL TROPICAL ATLC. BROAD CYCLONIC FLOW IS AROUND THE WAVE/LOW...BUT DOES NOT SHOW SIGNS OF WELL-DEFINED ORGANIZATION. CURRENTLY A CLUSTER OF STRONG CONVECTION IS FROM 21N-23N BETWEEN 33W-37W. ISOLATED MODERATE CONVECTION IS FROM 17N-21N BETWEEN 35W-40W. DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 20N16W CONTINUING TO THE CAPE VERDE ISLANDS AT 17N27W. THE MONSOON TROUGH THEN SPLITS DUE TO THE NW MOTION OF THE TROPICAL WAVE/LOW IN THE CENTRAL ATLC. THE AXIS BEGINS AGAIN AT THE LOW CENTER AT 18N37W ALONG 13N40W 8N48W. THE ITCZ CONTINUES AT 8N48W TO 11N61W. ISOLATED MODERATE CONVECTION IS OFF THE COAST OF AFRICA FROM 10N-16N BETWEEN 17W-25W ASSOCIATED WITH THE NEXT TROPICAL WAVE THAT WILL EMERGE OFF THE COAST LIKELY TONIGHT. SIMILAR ACTIVITY IS FROM 11N-13N BETWEEN 43W-46W. ...DISCUSSION... THE GULF OF MEXICO... TROPICAL STORM ISAAC CONTINUES TO IMPACT THE EASTERN GULF OF MEXICO AS IT MOVES THROUGH THE FLORIDA STRAITS INTO THE SE GULF. WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ARE ACROSS MUCH OF THE FLORIDA PENINSULA AND FLORIDA KEYS. FLOODING IS POSSIBLE THROUGHOUT THE FLORIDA KEYS AND THE SOUTHERN HALF OF THE FLORIDA PENINSULA. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON ISAAC. ELSEWHERE ACROSS THE GULF...WEAK SURFACE RIDGING IS OVER THE FAR WESTERN GULF EXTENDING FROM A HIGH CENTER OVER NORTHERN GEORGIA. DRY AIR ALOFT IS WRAPPING AROUND AN INVERTED UPPER TROUGH EXTENDING FROM CENTRAL LOUISIANA TO THE YUCATAN PENINSULA...WHICH IS HELPING PROVIDE FAIR CONDITIONS WEST OF 89W. STORMY CONDITIONS WILL BEGIN TO SPREAD INTO THE CENTRAL AND NORTHERN GULF AS ISAAC BEGINS A MORE NORTHWESTWARD TRACK. INTERESTS IN THE NORTHERN GULF SHOULD MONITOR THE PROGRESS OF ISAAC CLOSELY. THE CARIBBEAN SEA... EVEN THOUGH TROPICAL STORM ISAAC HAS MOVED NORTH OF THE BASIN...PORTIONS OF THE NORTHERN CARIBBEAN ARE STILL FEELING THE IMPACTS. SHOWERS AND ISOLATED THUNDERSTORMS ARE ACROSS CENTRAL CUBA FROM 19N-23N BETWEEN 77W-81W. REPORTS FROM CUBA STILL INDICATE THAT HEAVY AMOUNTS OF RAIN HAVE FALLEN WITHIN THE LAST 24 HOURS WITH SOME AREAS SUCH AS SAN ANTONIA DEL SUR IN GUANTANAMO RECEIVING OVER 14 INCHES. OTHER AREAS IN GUANTANAMO AS WELL AS SANTIAGO DE CUBA HAVE REPORTED ANYWHERE FROM 4 TO 8 INCHES. WITH RAIN STILL FALLING...FLOODING AND MUDSLIDES ARE STILL POSSIBLE ACROSS THE ISLAND. HISPANIOLA IS CURRENTLY DRY...BUT WIDESPREAD MOISTURE STILL COVERS THE EASTERN CARIBBEAN. AN UPPER LEVEL LOW CENTERED NORTH OF THE VIRGIN ISLANDS NEAR 20N64W IS PROVIDING WESTERLY FLOW ALOFT ACROSS THE NE CARIBBEAN...WHICH IS DRAWING MOISTURE FROM THE EASTERN EXTENT OF ISAAC. WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS COVER MUCH OF THE EASTERN CARIBBEAN E OF 72W. LUCKILY SOME DRY AIR IS SINKING SOUTHWARD FROM THE ATLC KEEPING THE ALREADY SATURATED GROUNDS OF THE NE ISLANDS DRY. THE MAJORITY OF THE WESTERN CARIBBEAN...BESIDES PORTIONS OF CUBA...IS MOSTLY DRY DUE TO DRY AIR ALOFT AROUND A WEAK UPPER LEVEL RIDGE COVERING THE WESTERN HALF OF THE BASIN. CYCLONIC SURFACE FLOW IS STILL PRESENT ACROSS THE NW CARIBBEAN DUE TO THE CIRCULATION OF ISAAC. STRONG SHOWERS/THUNDERSTORMS ARE PRESENT ACROSS PORTIONS OF CENTRAL AMERICA ALONG THE MONSOON TROUGH AXIS WHICH EXTENDS FARTHER NORTH THAN USUAL FROM WESTERN HONDURAS DOWN WESTERN NICARAGUA AND ACROSS COSTA RICA AND PANAMA TO NORTHERN COLUMBIA. CONDITIONS ACROSS CUBA SHOULD IMPROVE AS ISAAC MOVES FURTHER INTO THE GULF OF MEXICO. HOWEVER... THE MOISTURE CURRENTLY OVER THE EASTERN CARIBBEAN IS EXPECTED TO MOVE WESTWARD OVER THE NEXT SEVERAL DAYS AND COULD BRING ANOTHER BATCH OF RAIN TO BOTH HISPANIOLA AND CUBA. THE ATLANTIC OCEAN... TROPICAL STORM ISAAC IS PRODUCING SHOWERS AND ISOLATED THUNDERSTORMS ACROSS PORTIONS OF THE BAHAMAS INTO THE FLORIDA PENINSULA W OF 75W. THE REMAINDER OF THE W ATLC IS UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR WRAPPING AROUND AN UPPER LEVEL RIDGE CENTERED NEAR 29N73W. AN UPPER LEVEL LOW IS JUST N OF THE VIRGIN ISLANDS NEAR 20N63W PRODUCING A FEW ISOLATED SHOWERS/THUNDERSTORMS FROM 20N-23N BETWEEN 62W-67W. A SURFACE TROUGH...REMNANTS OF JOYCE...STILL EXISTS FROM 27N59W TO 24N59W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE TO THE NORTH FROM 28N-32N BETWEEN 59W-63W. THE REMAINDER OF THE ATLC IS DOMINATED BY BROAD SURFACE RIDGING AROUND A PAIR OF HIGH CENTERS N OF THE AREA. THE RIDGE IS SUPPORTED BY A BROAD UPPER LEVEL RIDGE CENTERED NEAR 31N49W WITH A SECOND UPPER RIDGE CENTERED NEAR 22N26W. THE LAST VISIBLE SATELLITE IMAGES ALONG WITH GOES-R ENHANCEMENT IMAGERY INDICATE AN AREA OF DUST EXTENDS BETWEEN THE TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC AND THE SURFACE TROUGH IN THE CENTRAL ATLC TO THE NORTH. AN AREA OF DUST ALSO EXTENDS OFF THE COAST OF AFRICA BEHIND THE WAVE AND AROUND A WAVE JUST EMERGING OFF THE COAST. 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