000 AXNT20 KNHC 251150 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... TROPICAL STORM OPHELIA IS CENTERED NEAR 18.4N 59.5W AT 25/0900 UTC OR ABOUT 205 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING W AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/ WTNT21 KNHC FOR MORE DETAILS. OPHELIA REMAINS UNDER SW SHEAR. SCATTERED MODERATE/STRONG CONVECTION IS FROM 15N-19N BETWEEN 52W-55W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 45 NM OF LINE FROM 17N56W TO 19N58W. TROPICAL STORM PHILIPPE IS CENTERED NEAR 12.0N 29.8W AT 25/0900 UTC OR ABOUT 355 NM W-SW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING W-NW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. PHILIPPE HAS BECOME A BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. SCATTERED STRONG CONVECTION IS WITHIN 60 NM OF THE CENTER IN THE NW QUADRANT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 10N-13N BETWEEN 29W-33W. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED 17N41W TO 10N39W MOVING W 5-10 KT. WAVE REMAINS BETWEEN TROPICAL STORMS OPHELIA AND PHILIPPE AND WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS. THERE IS VIRTUALLY NO CLOUD SIGNATURE ON SATELLITE IMAGERY WITH NO ASSOCIATED SHOWERS/CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA BUT DOES NOT ENTER THE E TROPICAL ATLC. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 5N-10N E OF 16W TO THE COAST OF SW AFRICA... WITHIN 90 NM ALONG THE COAST OF GUINEA-BISSAU...AND WITHIN 75/90 NM OF LINE FROM 5N33W 7N43W TO 7N50W. ...DISCUSSION... GULF OF MEXICO... THE WEAKENING STATIONARY FRONT EXTENDS ACROSS THE FLORIDA PANHANDLE JUST W OF TALLAHASSEE THEN ACROSS MOBILE BAY ALABAMA TO SE LOUISIANA SUPPORTED BY A BROAD UPPER TROUGH THAT COVERS E HALF OF THE US TO THE EASTERN SEABOARD AND INTO THE GULF N OF 23N GIVING THE GULF SE FLOW ALOFT. MOST OF N GULF IS DOMINATED BY STRONG SUBSIDENCE AND DRY STABLE AIR THUS THE FRONT IS NOT PRODUCING ANY SHOWERS. A SURFACE TROUGH EXTENDS ACROSS THE SE GULF FROM 27N85W TO 21N91W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS SE OF A LINE FROM N OF CEDAR KEY FLORIDA NEAR 30N83W TO 23N92W. THE REMAINDER OF THE GULF REMAINS UNDER REMARKABLY CLEAR SKIES AGAIN THIS MORNING. THE WEAKENING STATIONARY FRONT WILL GRADUALLY DISSIPATE LATER TODAY. HIGH PRESSURE WILL BUILD ALONG 27N THROUGH TUE THEN SHIFT N WED AND THU. CARIBBEAN SEA... AN UPPER LOW IS OVER THE NW CARIBBEAN CENTERED JUST S OF THE CAYMAN ISLANDS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF LINE FROM 17N73W ACROSS JAMAICA TO THE YUCATAN PENINSULA NEAR 20N87W TO INLAND OVER CUBA AND SW HAITI AND THROUGH THE YUCATAN CHANNEL. AN UPPER RIDGE IS OVER THE SW CARIBBEAN EXTENDING FROM E PANAMA ACROSS NE NICARAGUA/NE HONDURAS TO CENTRAL BELIZE PROVIDING A DIFFLUENT ENVIRONMENT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 12N AND S OF A LINE FROM THE YUCATAN PENINSULA NEAR 20N87W ALONG 16N80W. AN UPPER LOW LOCATED N OF THE DOMINICAN REPUBLIC EXTENDS S OVER THE NE CARIBBEAN GENERATING ISOLATED SHOWERS OVER THE N CARIBBEAN ISLANDS FROM THE VIRGIN ISLANDS TO THE DOMINICAN REPUBLIC. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 11N75W INTO THE E PACIFIC REGION ACROSS NICARAGUA NEAR 12N84W GENERATING SCATTERED SHOWERS/ THUNDERSTORMS S OF 12N BETWEEN 74W-84W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER CLEAR SKIES AGAIN THIS MORNING. TROPICAL STORM OPHELIA WILL CONTINUE TO MOVE NE OF THE LEEWARD/ VIRGIN ISLANDS THROUGH MON NIGHT. A WEAK TROPICAL WAVE IS EXPECTED TO ENTER THE THE E CARIBBEAN THU. ATLANTIC OCEAN... A NARROW UPPER RIDGE IS OVER THE FAR W ATLC FROM THE CENTRAL BAHAMAS TO NEAR 30N78W PROVIDING A DIFFLUENT ENVIRONMENT ALOFT WITH A SURFACE TROUGH EXTENDING FROM JUST W OF GRAND BAHAMA ISLAND THROUGH A WEAK 1013 MB LOW ALONG THE FLORIDA COAST NEAR MELBOURNE TO BEYOND 32N81W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 29N ACROSS THE THE BAHAMA ISLANDS TO OVER CUBA BETWEEN 76W-80W WITH ISOLATED SHOWERS COVERING THE AREA N OF 29N BETWEEN 76W-80W. A BROAD UPPER RIDGE DOMINATES THE W ATLC ANCHORED ABOUT 150 NM NW OF BERMUDA PROVIDING DRY STABLE AIR OVER THE AREA N OF 25N BETWEEN 45W-75W. AN UPPER TROUGH EXTENDS FROM AN UPPER LOW IN THE SW ATLC N OF THE DOMINICAN REPUBLIC NEAR 21N69W TO OVER THE E CARIBBEAN BUT IS ONLY PRODUCING POSSIBLE ISOLATED SHOWERS S OF 22N TO OVER THE CARIBBEAN ISLANDS BETWEEN THE VIRGIN ISLANDS AND THE DOMINICAN REPUBLIC. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF W INTO THE CENTRAL ATLC N OF 23N BETWEEN 45W-75W ANCHORED BY 1024 MB HIGH JUST E OF BERMUDA. AN UPPER TROUGH DIPS S OVER THE E ATLC N OF 23N BETWEEN 20W-50W SUPPORTING A SURFACE TROUGH THAT ENTERS THE REGION NEAR 32N29W TO 29N33W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM E OF THE TROUGH. A WEAK SURFACE RIDGE COVERS THE REMAINDER OF THE E ATLC ANCHORED BY A 1019 MB HIGH NEAR MADEIRA ISLANDS. THE SURFACE TROUGH/LOW IN THE W ATLC WILL SLOWLY LIFT N OF THE AREA TODAY. TROPICAL STORM OPHELIA WILL TRACK NW THROUGH TUE NIGHT THEN TURN MORE NORTHERLY THROUGH THU EVENING. THE WEAK TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE W TROPICAL ATLC REACHING THE E CARIBBEAN THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW