000 AXNT20 KNHC 261203 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM ISAAC AT 26/1200 UTC IS NEAR 23.5N 80.0W. THIS POSITION IS ABOUT 135 MI...220 KM ESE OF KEY WEST FLORIDA...OR ABOUT 155 MI...245 KM E OF HAVANA CUBA. ISAAC IS MOVING WNW AT 17 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 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. THE RAIN IMPACTS OF ISAAC SPREAD ACROSS A LARGE AREA FROM THE ERN CARIBBEAN ALL THE WAY INTO THE SE GULF OF MEXICO. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE ACROSS THE BAHAMAS AND STRAITS OF FLORIDA S OF 28N W OF 73W...INCLUDING THE NRN COASTAL WATERS OF HISPANIOLA...CUBA...AND TURKS AND CAICOS. SIMILAR CONVECTION IS OVER THE SE GULF OF MEXICO S OF 27N E OF 85W. A 1009 MB LOW AND ASSOCIATED TROPICAL WAVE AXIS IS CENTERED NEAR 16N34W MOVING WNW AT 10-15 KT. THIS SYSTEM IS EMBEDDED IN THE BROAD SCALE MONSOON GYRE ON SATELLITE IMAGERY...WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT ACROSS MUCH OF THE CENTRAL TROPICAL ATLC. THE SYSTEM REMAINS DISORGANIZED DUE TO UNFAVORABLE UPPER LEVEL WINDS AND A THICK LAYER OF SAHARAN DUST SURROUNDING THE WAVE AND ASSOCIATED LOW. SCATTERED MODERATE CONVECTION IS FROM 15N-21N BETWEEN 31W-37W. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR DEVELOPMENT...AND THIS LOW COULD BECOME A TROPICAL DEPRESSION OVER THE NEXT DAY OR TWO. 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 17N20W CONTINUING WSW ALONG 18N25W TO THE SPECIAL FEATURE 1009 MB LOW AND ASSOCIATED TROPICAL WAVE NEAR 16N34W AND ALONG 10N39W TO 8N48W...WHERE THE ITCZ CONTINUES ALONG 9N55W TO NEAR THE COAST OF VENEZUELA AT 10N64W. WHILE NO CONVECTION IS NOTED AROUND THE ITCZ...SCATTERED MODERATE CONVECTION IS WITHIN 70 NM ON EITHER SIDE OF THE MONSOON TROUGH BETWEEN 37W-47W...AND OFF THE COAST OF WEST AFRICA FROM 8N-16N E OF 22W. ...DISCUSSION... GULF OF MEXICO... SEVERAL OUTER BANDS OF STRONG CONVECTION ASSOCIATED TO TROPICAL STORM ISAAC HAVE MADE THEIR WAY IN ACROSS THE SRN FLORIDA PENINSULA AND THE ERN GULF THROUGH THE STRAITS OF FLORIDA THIS MORNING...AS MOSAIC DOPPLER RADAR IMAGERY CURRENTLY INDICATES THE ACTIVITY EXTENDS S OF 27N E OF 85W. WEATHER CONDITIONS ARE EXPECTED TO DETERIORATE ACROSS THE ERN GULF E OF 87W DURING THE NEXT 24 HOURS...AS ISAAC ENTERS THE BASIN AND GAINS STRENGTH TO POSSIBLE HURRICANE STATUS. ALL INTERESTS IN THE EASTERN GULF SHOULD MONITOR THE PROGRESS OF ISAAC. WEAK SURFACE RIDGING AND DRY AIR ALOFT EMBEDDED IN AN ELONGATED UPPER LOW OFF THE NRN COAST OF THE YUCATAN PENINSULA ARE KEEPING THE REMAINDER OF THE BASIN UNDER FAIR WEATHER CONDITIONS THIS MORNING. CARIBBEAN SEA... ALTHOUGH THE CENTER OF TROPICAL STORM ISAAC IS OUT OF THE CARIBBEAN SEA...THE BROAD CYCLONIC WIND FIELD AND AVAILABLE MOISTURE CONTINUE TO GENERATE STRONG CONVECTION...GUSTY WINDS AND SIGNIFICANT RAINFALL ACROSS THE NE AND N-CENTRAL BASINS ...ESPECIALLY HISPANIOLA AND CUBA...WHERE EARLIER REPORTS FROM THIS COUNTRY INDICATED RAINFALL ACCUMULATIONS OF UP TO NEAR 5 INCHES IN THE LAST 3 HOURS OVER THE FAR SE PORTION OF THE ISLAND. FLOODING AND MUDSLIDES ARE LIKELY ACROSS THIS REGION AS SATELLITE IMAGERY CONTINUES TO SHOW RAINFALL DEVELOPMENT AGAIN THIS MORNING. AN EARLIER SCATTEROMETER PASS REVEALED A SURFACE TROUGH EXTENDING FROM THE COAST OF CUBA NEAR 21N78W TO 19N85W. DUE TO THE LARGE CIRCULATION...MUCH OF THE NORTHERN CARIBBEAN WILL CONTINUE TO EXPERIENCE GUSTY WINDS AND HEAVY RAIN AS THE STORM CONTINUES TOWARDS THE GULF OF MEXICO. THE NW AND SW CARIBBEAN ARE THE ONLY AREAS STILL UNDER MOSTLY FAIR CONDITIONS DUE TO DRY AIR ALOFT. ALL INTERESTS IN THE NORTHERN CARIBBEAN SHOULD CONTINUE TO MONITOR THE PROGRESS OF ISAAC. 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 S-EASTERN CONUS IS HELPING PRODUCE SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE BAHAMAS AND STRAITS OF FLORIDA S OF 28N W OF 73W...ALSO INCLUDING THE NRN COASTAL WATERS OF HISPANIOLA...CUBA...AND TURKS AND CAICOS. THE UPPER LEVEL OUTFLOW-CIRRUS FROM ISAAC COVERS THE MAJORITY OF THE WEST ATLC W OF 71W. ALL INTERESTS IN THE FAR WESTERN ATLC SHOULD CONTINUE TO MONITOR THE PROGRESS OF ISAAC. A BROAD UPPER LOW IS CENTERED NEAR 20N60W WITH MINIMAL ACTIVITY WITHIN 100 NM NE OF THE UPPER LOW CENTER. THE REMAINDER OF THE ATLC BASIN DISCUSSION AREA IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1024 MB HIGH NEAR 32N50W AND A 1022 MB HIGH NEAR 33N28W. THE FAIR WEATHER IS ENHANCED ALOFT BY SAHARAN DUST NOTED ON METEOSAT-9 AND GOES-R ENHANCEMENT IMAGERY. EMBEDDED IN THIS DRY ENVIRONMENT...AN UPPER LOW WOBBLES NEAR 33N18W. EXPECT WEATHER CONDITIONS TO CONTINUE TO DETERIORATE OVER THE WRN ATLC TODAY AS TROPICAL STORM ISAAC MOVES INTO THE FLORIDA STRAITS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA