000 AXNT20 KNHC 280559 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED SEP 28 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 PHILIPPE IS CENTERED NEAR 16.1N 37.0W AT 28/0300 UTC OR ABOUT 750 NM W OF THE CAPE VERDE ISLANDS MOVING W-NW AT 9 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. PHILIPPE REMAINS SHEARED WITH THE DEEP CONVECTION TO THE N OF THE LOW LEVEL CENTER. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 60 NM OF 17.5N BETWEEN 31W-37W. TROPICAL DEPRESSION OPHELIA IS CENTERED NEAR 18.4N 59.5W AT 28/0300 UTC OR ABOUT 205 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING NW AT 3 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 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. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 14N-20N BETWEEN 57W-62W INCLUDING THE LESSER ANTILLES. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED FROM 1ON25W TO 4N27W MOVING W 15-20 KT. WAVE IS DIFFICULT TO DISCERN IN SATELLITE IMAGERY BUT IS EVIDENT IN LOW LEVEL STREAMLINE ANALYSIS. NO ASSOCIATED SHOWERS/CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA ENTERING THE E TROPICAL ATLC NEAR 17N16W TO 14N20W. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION ARE WITHIN 90 NM ALONG THE COAST W AFRICA BETWEEN LIBERIA AND GUINEA AND WITHIN 60/75 NM OF LINE FROM 10N36W TO 8N40W. ...DISCUSSION... GULF OF MEXICO... THE LARGE UPPER LOW IS BEGINNING TO MOVE E AND IS NOW CENTERED OVER THE GREAT LAKES EXTENDING A BROAD UPPER TROUGH INTO THE NE GULF AND W ATLC N OF 26N E OF 90W SUPPORTING A STATIONARY FRONT THAT REMAINS INLAND OVER THE SE CONUS AND NOT PRODUCING ANY SHOWER/THUNDERSTORM ACTIVITY IN THE GULF. A SURFACE TROUGH AT 28/0300 UTC IS INLAND OVER NE FLORIDA AS INDICATED BY A WIND SHIFT WITH A SECOND SURFACE TROUGH OVER SE FLORIDA EXTENDING FROM LAKE OKEECHOBEE ACROSS THE UPPER FLORIDA KEYS TO 24N81W PRODUCING SCATTERED SHOWERS ALONG THE TROUGH AXIS. A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED OVER S MEXICO. WEAK HIGH PRESSURE COVERS THE GULF E OF 94W WITH A 1014 MB HIGH LOCATED NEAR 27N86W AT 28/0300 UTC. CLEAR SKIES DOMINATE THE GULF TONIGHT WITH THE EXCEPTION OF SOME FAST MOVING HIGH CLOUDS ACROSS THE S GULF. WEAK HIGH PRESSURE WILL PERSIST THROUGH WED NIGHT THEN SHIFT TO THE NW GULF THU AND FRI. A COLD FRONT WILL MOVE INTO THE NW GULF FRI REACHING FROM TAMPA FLORIDA TO NE MEXICO SAT AND FROM S FLORIDA TO THE BAY OF CAMPECHE SUN. STRONG HIGH PRESSURE WILL THEN BUILD SE BEHIND THE FRONT ACROSS THE N/CENTRAL GULF. CARIBBEAN SEA... THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS OVER THE NW CARIBBEAN N OF 16N W OF 70W PROVIDING A DIFFLUENT ENVIRONMENT TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 60 NM ALONG THE COAST OF CUBA AND HAITI. A SMALL UPPER LOW IS INLAND OVER PRODUCING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS INLAND OVER HONDURAS AND GUATEMALA WITH SOME ISOLATED SHOWERS MOVING OVER THE GULF OF HONDURAS. THE MONSOON TROUGH EXTENDS FROM COLOMBIA S OF PANAMA SO IS NOT GENERATING ANY ACTIVITY IN THE SW CARIBBEAN. THE UPPER RIDGE ASSOCIATE WITH OPHELIA EXTENDS ACROSS THE LESSER ANTILLES TO OVER THE E CARIBBEAN. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES TONIGHT. TROPICAL STORM OPHELIA IS FORECAST TO INTENSIFY TO TROPICAL STORM STRENGTH LATER TODAY AS IT MOVES AWAY FROM THE CARIBBEAN. OTHERWISE...A WEAK PRESSURE PATTERN WILL EXIST OVER MUCH OF THE AREA THROUGH SUN. ATLANTIC OCEAN... THE UPPER TROUGH OVER THE GULF OF MEXICO AND THE SE CONUS EXTENDS OVER THE W ATLC WITH A SHORTWAVE UPPER TROUGH EXTENDING FROM THE N BAHAMA ISLANDS TO 32N76W AND A NARROW UPPER RIDGE TO THE E EXTENDS FROM THE N COAST OF CUBA NEAR 22N78W TO BEYOND 32N72W PROVIDING A DIFFLUENT ENVIRONMENT ALOFT TO GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS OVER THE BAHAMA ISLANDS AND WITHIN 120 NM OF LINE FROM 26N76W TO BEYOND 32N75W. AN ELONGATED UPPER TROUGH EXTENDS FROM 31N69W THROUGH AN UPPER LOW NEAR 26N68W TO THE VIRGIN ISLANDS/PUERTO RICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 60/75 NM OF LINE FROM 22N64W TO 28N68W. THE UPPER RIDGE ASSOCIATED WITH OPHELIA COVERS THE AREA FROM 11N-26N BETWEEN 54W-63W. A WEAK SURFACE RIDGE DOMINATES THE W AND CENTRAL ATLC N OF 25N BETWEEN 55W-75W ANCHORED BY 1020 MB HIGH JUST W-SW OF BERMUDA. AN UPPER TROUGH EXTENDS S OVER THE E ATLC TO 21N BETWEEN 20W-45W SUPPORTING A COLD FRONT THAT IS N OF THE DISCUSSION AREA AND TRAILING A SURFACE TROUGH THAT EXTENDS FROM 31N41W TO 25N50W. ISOLATED CLUSTERS OF SHOWERS/THUNDERSTORMS DOT THE AREA FROM 27N-30N BETWEEN 34W-52W. A WEAK SURFACE RIDGE COVERS THE REMAINDER OF THE E ATLC ANCHORED BY A 1022 MB HIGH NE OF THE MADEIRA ISLANDS. HIGH PRESSURE OVER THE W/CENTRAL ATLC WILL REMAIN STATIONARY BUT GRADUALLY WEAKEN THROUGH THU THEN SHIFT NE OF THE AREA FRI AND SAT. TROPICAL DEPRESSION OPHELIA IS FORECAST TO INTENSITY TO HURRICANE STRENGTH AS IT MOVES THROUGH THE CENTRAL ATLC FRI THROUGH SAT. A WEAK FRONT WILL MOVE INTO THE FAR W ATLC THU AND WILL REACH THE CENTRAL BAHAMAS SAT. A STRONGER FRONT WILL MOVE INTO THE FAR W ATLC SAT AND RAPIDLY SHIFT E MERGING WITH THE WEAK FRONT SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW