000 AXNT20 KNHC 120550 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAY SEP 12 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0345 UTC. ...SPECIAL FEATURES... TROPICAL STORM FRED IS CENTERED NEAR 18.0N 33.6W AT 12/0300 UTC OR ABOUT 565 NM WNW OF THE CAPE VERDE ISLANDS MOVING ENE AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. DEEP CONVECTION IS DISPLACED TO THE N DUE TO SLY SHEAR. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60/75 NM OF LINE FROM 18N31W TO 22N34W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 20W/21W S OF 20N WITH A 1010 MB LOW ALONG THE WAVE NEAR 12N MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN A DEEP LAYERED MOISTURE MAXIMUM AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER..CONVECTION IS NOT CONCENTRATED ALONG THE WAVE AXIS. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 11N-18N BETWEEN 18W-23W. TROPICAL WAVE IS ALONG 82W/83W S OF 20N MOVING W NEAR 15 KT. WAVE CONTINUES TO LAG THE DEEP LAYERED MOISTURE MAXIMUM AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED SHOWERS MAY BE FOUND WITHIN 60 NM OF THE WAVE FROM 13N-17N. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N14W 8N24W 13N36W 10N62W. SCATTERED MODERATE/STRONG CONVECTION IS INLAND AND WITHIN 75 NM ALONG THE COAST OF W AFRICA FROM 9N-13N. SCATTERED MODERATE/ ISOLATED STRONG CONVECTION IS WITHIN 60/75 NM OF LINE FROM 10N16W TO 6N20W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA FROM 7N-13N BETWEEN 24W-45W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH EXTENDS FROM THE W ATLC ACROSS THE FLORIDA PENINSULA NEAR LAKE OKEECHOBEE INTO THE GULF ALONG 26N85W TO THE TEXAS COAST NEAR CORPUS CHRISTI. AN UPPER TROUGH EXTENDS FROM THE DESERT SW OVER TEXAS/MEXICO ALONG THE RIO GRANDE TO BROWNSVILLE TEXAS WHILE AN UPPER RIDGE EXTENDS FROM VERACRUZ MEXICO TO NE FLORIDA. THIS SCENARIO COUPLED WITH THE ABUNDANCE OF DEEP LAYER MOISTURE IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE E GULF E OF 90W TO JUST INLAND OVER THE FLORIDA PENINSULA...N OF THE SURFACE TROUGH TO INLAND OVER LOUISIANA WITH ISOLATED CLUSTERS OF SIMILAR ACTIVITY S OF 27N W OF 95W TO INLAND OVER MEXICO. CARIBBEAN SEA... AN UPPER RIDGE COVERS THE W CARIBBEAN EXTENDING FROM COSTA RICA TO THE CAYMAN ISLANDS WHILE AN UPPER TROUGH COVERS THE E CARIBBEAN EXTENDING FROM AN UPPER LOW N OF PUERTO RICO. DIFFLUENCE ALOFT FROM THE UPPER RIDGE IN THE GULF OF MEXICO COUPLED WITH THE ABUNDANCE OF DEEP LAYER MOISTURE IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 20N ACROSS CUBA AND THROUGH THE YUCATAN CHANNEL W OF 77W TO THE YUCATAN PENINSULA. SIMILAR ACTIVITY IS IN THE FAR SW CARIBBEAN...INLAND AND WITHIN 60 NM ALONG THE COAST OF W PANAMA TO S NICARAGUA S OF 12N W OF 79W. THERE ARE SOME ISOLATED SHOWERS/THUNDERSTORMS INLAND OVER SOUTHERN HISPANIOLA AND DRIFTING INTO THE COASTAL WATERS. OTHERWISE THE E CARIBBEAN E OF 80W IS REMARKABLY CLEAR TONIGHT. ATLANTIC OCEAN... A SURFACE TROUGH ENTERS THE REGION THROUGH 32N74W EXTENDING SW ACROSS THE FLORIDA PENINSULA NEAR LAKE OKEECHOBEE AND INTO THE GULF OF MEXICO. DIFFLUENCE ALOFT FROM THE UPPER RIDGE IN THE GULF OF MEXICO IS ENHANING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 30N W OF 77W TO INLAND OVER THE FLORIDA PENINSULA AND INTO THE STRAITS OF FLORIDA. AN UPPER TROUGH DIPS S OVER THE W ATLC TO 23N BETWEEN 70W-80W WITH A NARROW UPPER RIDGE JUST TO THE E EXTENDING FROM THE WINDWARD PASSAGE TO 32N67W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS WITHIN 75 NM OF LINE FROM 25N71W TO 29N69W. AN UPPER LOW IS N OF PUERTO RICO NEAR 24N65W WITH THE UPPER TROUGH DIPPING S OVER THE E CARIBBEAN BUT IS NOT GENERATING ANY SIGNIFICANT WEATHER. A BROAD UPPER TROUGH COVERS THE N/CENTRAL ATLC N OF 28N BETWEEN 37W-56W WITH THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N39W EXTENDING SW ALONG 28N46W THEN W 29N53W THEN NW TO BEYOND 32N59W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE FRONTAL BOUNDARY. AN UPPER LOW IS S OF THE UPPER TROUGH/FRONT CENTERED NEAR 21N43W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 22N49W 18N51W TO 15N50W WITH NO SIGNIFICANT WEATHER. A BROAD UPPER RIDGE COVERS THE E ATLC FROM THE TROPICS TO 30N ANCHORED NEAR 18N20W AND PROVIDING THE SLY SHEAR OVER TROPICAL STORM FRED. $$ WALLACE