000 AXNT20 KNHC 250556 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...SPECIAL FEATURES... TROPICAL STORM OPHELIA IS CENTERED NEAR 18.3N 58.4W AT 25/0300 UTC OR ABOUT 270 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING W-NW AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. OPHELIA CONTINUES TO BE SHEARED WITH THE DEEP CONVECTION WELL REMOVED FROM THE CENTER. SCATTERED STRONG CONVECTION IS FROM 16N-19N BETWEEN 52W-55W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 17N-21N BETWEEN 51W-57W. TROPICAL STORM PHILIPPE IS CENTERED NEAR 11.6N 28.8W AT 25/0300 UTC OR ABOUT 320 NM SW OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING W-NW AT 11 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. PLEASE SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS FROM 9N-12N BETWEEN 28W-30W AND FROM 10N-13N BETWEEN 31W-32W. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED ALONG 39W/40W BETWEEN 10N-19N MOVING W NEAR 10 KT. WAVE IS TRAPPED BETWEEN TROPICAL STORMS OPHELIA AND PHILIPPE RESULTING IN THE WAVE SLOWING DOWN. WAVE REMAINS WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS WITH A WEAK SIGNATURE IN THE LOW CLOUDS ON SATELLITE IMAGERY. NO ASSOCIATED SHOWERS/ CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL ATLC NEAR 20N16W TO 17N19W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN A 45 NM RADIUS OF 15N20.5W WITH CLUSTERS OF SIMILAR CONVECTION WITHIN 120 NM ALONG THE COAST OF LIBERIA AND SIERRA LEONE. ...DISCUSSION... GULF OF MEXICO... THE WEAKENING STATIONARY FRONT EXTENDS INTO THE GULF ACROSS THE FLORIDA PANHANDLE JUST W OF TALLAHASSEE ALONG 30N88W TO 28N90W 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. THE 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 26N85W TO 23N90W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS SE OF A LINE FROM CEDAR KEY FLORIDA TO 24N91W. THE REMAINDER OF THE GULF REMAINS UNDER REMARKABLY CLEAR SKIES AGAIN TONIGHT. THE WEAKENING STATIONARY FRONT WILL GRADUALLY DISSIPATE THROUGH SUN NIGHT. HIGH PRESSURE WILL BUILD IN THE WAKE OF THE FRONT THROUGH TUE AND SHIFT N WED AND THU. CARIBBEAN SEA... AN UPPER LOW IS OVER THE NW CARIBBEAN CENTERED NEAR THE CAYMAN ISLANDS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF LINE FROM JAMAICA TO THE NE TIP OF THE YUCATAN PENINSULA TO OVER CUBA. AN UPPER RIDGE IS OVER THE SW CARIBBEAN EXTENDING FROM E PANAMA TO NE NICARAGUA PROVIDING A DIFFLUENT ENVIRONMENT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-18N W OF 81W TO OVER CENTRAL AMERICA AND IN THE GULF OF HONDURAS. AN UPPER LOW LOCATED N OF THE DOMINICAN REPUBLIC EXTENDS S OVER THE NE CARIBBEAN. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 11N76W INTO THE E PACIFIC REGION ACROSS COSTA RICA NEAR 10N84W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 12N BETWEEN 72W-84W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER CLEAR SKIES AGAIN TONIGHT. 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 31N76W PROVIDING A DIFFLUENT ENVIRONMENT ALOFT WITH A SURFACE TROUGH EXTENDING FROM JUST W OF GRAND BAHAMA ISLAND THROUGH A WEAK 1012 MB LOW NEAR 29N78W TO BEYOND 32N78W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 28N ACROSS THE THE BAHAMA ISLANDS TO OVER CUBA BETWEEN 74W-80W WITH ISOLATED SHOWERS COVERING THE AREA N OF 28N BETWEEN 75W-81W. A BROAD UPPER RIDGE DOMINATES THE W ATLC ANCHORED JUST N OF BERMUDA PROVIDING DRY STABLE AIR OVER THE AREA N OF 25N BETWEEN 50W-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. A BROAD SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC N OF 22N BETWEEN 37W-73W ANCHORED BY 1024 MB HIGH JUST NE OF BERMUDA. AN UPPER TROUGH DIPS S OVER THE E ATLC N OF 24N BETWEEN 20W-45W SUPPORTING A DISSIPATING COLD FRONT THAT ENTERS THE REGION NEAR 32N28W TO 29N35W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90 NM E OF THE FRONT. A WEAK SURFACE RIDGE COVERS THE REMAINDER OF THE E ATLC ANCHORED BY A 1020 MB HIGH NEAR MADEIRA ISLANDS. THE SURFACE TROUGH/LOW IN THE W ATLC WILL SLOWLY LIFT N OF THE AREA THROUGH SUN. TROPICAL STORM OPHELIA WILL TRACK NW THROUGH MON 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