000 AXNT20 KNHC 252355 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN SEP 25 2011 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 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM OPHELIA WAS DOWNGRADED TO A REMNANT AREA OF DISORGANIZED CONVECTION CENTERED NEAR 18.5N 60.9W AT 25/2100Z OR ABOUT 145 MI...235 KM E OF THE NORTHERN LEEWARD ISLANDS... MOVING W-NW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/ WTNT21 KNHC FOR MORE DETAILS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 16N-22N BETWEEN 54W-69W. TROPICAL STORM PHILIPPE IS CENTERED NEAR 13.2N 31.7W AT 25/2100Z OR ABOUT 500 MI...805 KM WSW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING NW AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE/STRONG CONVECTION IS AROUND THE WRN SEMI-CIRCLE FROM 10N-15N BETWEEN 31W-35W. PHILIPPE IS MOVING TOWARD A WEAKNESS IN THE SUBTROPICAL RIDGE. THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS IN THE CENTRAL ATLC ANALYZED FROM 17N43W TO 8N42W MOVING W 10-15 KT. LOW LEVEL SATELLITE DERIVED WINDS INDICATE WEAK CYCLONIC TURNING AROUND THE WAVE AXIS. THE WAVE IS BETTER DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY SHOWING A SURGE OF DEEP LAYER OF MOISTURE IN THE VICINITY OF THE WAVE AXIS. CURRENTLY NO DEEP CONVECTION ACCOMPANIES THE WAVE. ...ITCZ/MONSOON TROUGH... DUE TO THE LARGE SCALE CIRCULATION OF T.S. PHILIPPE...THE CENTRAL ATLC TROPICAL WAVE AND T.S. OPHELIA...THE OCEANIC MONSOON TROUGH ONLY EXTENDS FROM THE COAST OF WEST AFRICA NEAR 19N16W TO 16N19W. THE ITCZ IS NOT PRESENT. HOWEVER...SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS E OF 22W FROM 4N-17N DUE TO A MID-UPPER CYCLONIC CIRCULATION MOVING OFF THE COAST OF WEST AFRICA. AS PHILIPPE MOVES TOWARDS THE WNW...THE MONSOON TROUGH WILL SLOWLY BUILD BACK IN BEHIND IT. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY CONTINUES TO SHOW A BROAD UPPER TROUGH/CUT OFF LOW CENTERED OVER ERN IOWA. THE CYCLONIC FLOW ASSOCIATED TO THIS FEATURE PUSHES A LONGWAVE THAT SWINGS OVER THE NRN GULF... SUPPORTING A PAIR OF SURFACE TROUGHS OVER THE FLORIDA PENINSULA AND THE ERN GULF. THE MAIN ONE EXTENDS ACROSS THE SE CONUS SEABOARD...ENTERING THE FLORIDA PENINSULA ACROSS DAYTONA BEACH SW TO THE FLORIDA KEYS NEAR KEY WEST. THESE TWO FEATURES ARE GENERATING SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS OVER THE FAR ERN GULF...ESPECIALLY NEAR THE COASTAL WATERS OF THE WRN FLORIDA PENINSULA N OF 24N E OF 85W. FAIR WEATHER CONDITIONS ARE OBSERVED ELSEWHERE ACROSS THE BASIN THIS EVENING. EXPECT CONTINUED PRECIPITATION OVER FLORIDA...THE SE GULF...AND THE YUCATAN PENINSULA OVER THE NEXT 24 HOURS. CARIBBEAN SEA... MOSTLY FAIR WEATHER CONDITIONS WITH 10-15 KT ELY TRADE WIND FLOW ARE OBSERVED OVER MOST OF THE CARIBBEAN SEA THIS EVENING...WITH ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS ARE EMBEDDED IN THE FLOW. A WEAK UPPER CYCLONIC CIRCULATION IS OVER THE NW CARIBBEAN AND IS LIKELY ENHANCING THE ISOLATED CONVECTION IN THIS REGION. STRONGER SCATTERED CONVECTION IS OBSERVED IN THE FAR SW BASIN. LAST SATELLITE VISIBLE PICTURES OF THE DAY SHOWED CLUSTERS OF MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS S OF 13N W OF 67W... ASSOCIATED TO THE MONSOON TROUGH EXTENDING ACROSS SRN NICARAGUA INTO NRN COLOMBIA. COMPUTER MODELS SUGGEST THE CONVECTION WILL LIFT N OVER THE NEXT 24 HOURS AFFECTING THE CENTRAL CARIBBEAN. THE REMNANTS OF TROPICAL STORM OPHELIA ARE CURRENTLY E AND N OF THE LESSER ANTILLES AND HISPANIOLA. THIS CONVECTION IS EXPECTED TO REMAIN OUT OF THE DISCUSSION AREA. ATLANTIC OCEAN... WATER VAPOR IMAGERY CONTINUES TO SHOW A BROAD UPPER TROUGH/CUT OFF LOW CENTERED OVER ERN IOWA. THE CYCLONIC FLOW ASSOCIATED TO THIS FEATURE PUSHES A LONGWAVE THAT SWINGS OVER THE ESE CONUS... SUPPORTING A SURFACE TROUGH EXTENDING SSE ACROSS THE SEABOARD WITHIN 30-90 NM OFF THE COAST...ENTERING THE FLORIDA PENINSULA ACROSS DAYTONA BEACH. SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE WITHIN THE SAME DISTANCE AS THE SURFACE TROUGH AXIS. AN UPPER RIDGE IS AHEAD OF THIS AREA OF CONVECTION SUPPORTING A NEARLY STATIONARY 1022 MB HIGH CENTERED OVER BERMUDA AND PROVIDING FAIR/STABLE CONDITIONS TO A GREAT PART OF THE WRN ATLC N OF 22N BETWEEN 45W-77W. A WEAK UPPER LOW IS N OF HISPANIOLA. THIS FEATURE ALONG WITH THE REMNANTS OF OPHELIA IS GENERATING SCATTERED MODERATE TO STRONG CONVECTION ACROSS THE NRN COASTAL WATERS OF THE LESSER ANTILLES...PUERTO RICO...AND DOMINICAN REPUBLIC S OF 22N W OF 54W. A BROAD UPPER TROUGH COVERS THE ERN AND CENTRAL NORTH ATLC SUPPORTING AN AREA OF SCATTERED MODERATE CONVECTION N OF 27N BETWEEN 34W-42W. A 1020 MB HIGH IS E MADEIRA ISLANDS PROVIDING MOSTLY FAIR WEATHER ACROSS THE SE ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA