000 AXNT20 KNHC 121114 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC. ...SPECIAL FEATURES... TROPICAL STORM FRED IS CENTERED NEAR 17.8N 33.6W AT 12/0900 UTC OR ABOUT 560 NM WNW OF THE CAPE VERDE ISLANDS. FRED IS NOW STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1002 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. T.S. FRED HAS BEEN SHEARED TONIGHT WITH A SMALL AREA OF SCATTERED MODERATE CONVECTION WELL REMOVED FROM THE EXPOSED LOW LEVEL CENTER. CONVECTION IS FROM 19N-21N BETWEEN 32W-35W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 22W S OF 1920N WITH A 1010 MB LOW ALONG THE WAVE NEAR 12N MOVING W NEAR 10-15 KT. WAVE IS EMBEDDED WITHIN A DEEP LAYERED MOISTURE MAXIMUM AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY AND CONVECTION IS NOW MORE CONCENTRATED ALONG THE WAVE AXIS. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 90 NM OF LINE FROM 10N20W TO OVER THE CAPE VERDE ISLANDS NEAR 15N23W. TROPICAL WAVE IS ALONG 84W/85W S OF 20N MOVING W NEAR 15 KT. WAVE REMAINS TO THE E OF THE DEEP LAYERED MOISTURE MAXIMUM AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 45 NM OF LINE FROM 11N81W TO 17N84W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 14N15W 11N27W 11N35W 9N53W 9N62W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS INLAND AND WITHIN 150 NM ALONG THE COAST OF W AFRICA FROM 9N-13N. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF LINE FROM 9N17W TO 6N21W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA FROM 8N-12N BETWEEN 31W-46W AND FROM 9N-13N BETWEEN 55W-61W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH EXTENDS FROM THE W ATLC TO A WEAK 1013 MB LOW OVER THE FLORIDA PENINSULA JUST N OF LAKE OKEECHOBEE INTO THE GULF ALONG 27N85W ALONG 29N94W TO A 1008 MB LOW ALONG THE COAST OF TEXAS BETWEEN CORPUS CHRISTI AND BROWNSVILLE. AN UPPER TROUGH EXTENDS FROM THE DESERT SW OVER TEXAS/MEXICO ALONG THE RIO GRANDE TO NEAR THE 1008 SURFACE LOW WHILE AN UPPER RIDGE EXTENDS FROM VERACRUZ MEXICO TO NE FLORIDA. THIS SCENARIO COUPLED WITH THE ABUNDANCE OF DEEP LAYER MOISTURE IS GENERATING SCATTERED/HEAVY SHOWERS WITH SCATTERED/NUMEROUS THUNDERSTORMS ACROSS THE W GULF S OF THE SURFACE TROUGH W OF 94W INTO THE BAY OF CAMPECHE. SCATTERED/HEAVY SHOWERS WITH ISOLATED THUNDERSTORMS OVER THE E GULF E OF A LINE FROM CUBA NEAR 23N84W TO LOUISIANA NEAR 29N90W LEAVING ISOLATED SHOWERS ACROSS THE CENTRAL GULF. CARIBBEAN SEA... AN UPPER RIDGE COVERS THE W CARIBBEAN EXTENDING FROM COSTA RICA TO W OF THE CAYMAN ISLANDS WHILE AN UPPER TROUGH COVERS THE E CARIBBEAN EXTENDING FROM AN UPPER LOW N OF PUERTO RICO. EVEN THOUGH THERE IS DIFFLUENCE ALOFT...THE SURFACE HAS BEGUN TO DRY OUT OVER THE W CARIBBEAN LEAVING ISOLATED SHOWERS N OF 20N N OF 20N TO ACROSS CUBA BETWEEN 77W-83W. SCATTERED STRONG CONVECTION ASSOCIATED THE ITCZ CROSSING THE SW CARIBBEAN FROM COLOMBIA AND PANAMA IS S OF S OF 11N E OF 78W TO INLAND OVER COLOMBIA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 10N TO INLAND OVER PANAMA FROM 78W-82W. ISOLATED SHOWERS/THUNDERSTORMS CONTINUE INLAND AND WITHIN 60 NM ALONG THE S COAST OF HISPANIOLA. OTHERWISE THE E CARIBBEAN E OF 80W IS REMARKABLY CLEAR THIS MORNING. ATLANTIC OCEAN... A SURFACE TROUGH ENTERS THE REGION THROUGH 32N74W EXTENDING SW TO A 1013 MB LOW OVER THE FLORIDA PENINSULA JUST N OF LAKE OKEECHOBEE AND INTO THE GULF OF MEXICO. DIFFLUENCE ALOFT FROM THE UPPER RIDGE IN THE GULF OF MEXICO IS ENHANING SCATTERED SHOWERS/THUNDERSTORMS FROM 26N-30N W OF 76W TO INLAND OVER THE FLORIDA PENINSULA AND BETWEEN THE BAHAMAS AND CUBA FROM 76W-78W. AN UPPER TROUGH DIPS S OVER THE W ATLC TO 23N BETWEEN 70W-77W WITH WEAK COLD FRONT ENTERING THE REGION NEAR 32N69W TO 25N74W. A NARROW UPPER RIDGE IS JUST TO THE E EXTENDING FROM HAITI TO 32N66W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/THUNDERSTORMS WITHIN 200 NM E OF THE FRONT AND WITHIN 75 NM W OF THE FRONT S OF 28N. AN UPPER LOW IS N OF PUERTO RICO NEAR 23N65W WITH THE UPPER TROUGH DIPPING S OVER THE E CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N TO INLAND OVER HISPANIOLA BETWEEN 69W-70W. A BROAD UPPER TROUGH COVERS THE N/CENTRAL ATLC N OF 28N BETWEEN 35W-56W WITH THE ASSOCIATED COLD FRONT ENTERING THE REGION NEAR 32N37W EXTENDING SW ALONG 28N45W THEN W 28N52W THEN NW TO BEYOND 32N60W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90/120 NM EITHER SIDE OF THE FRONTAL BOUNDARY. A WEAKENING UPPER LOW IS S OF THE UPPER TROUGH/FRONT CENTERED NEAR 21N41W SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 22N49W TO 15N51W WITH NO SIGNIFICANT WEATHER. A BROAD UPPER RIDGE COVERS THE E ATLC FROM THE TROPICS TO 30N ANCHORED NEAR 19N21W AND PROVIDING THE SLY SHEAR OVER TROPICAL STORM FRED. $$ WALLACE