000 AXNT20 KNHC 102337 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU SEP 10 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... HURRICANE FRED IS CENTERED NEAR 17.3N 35.1W AT 10/2100 UTC OR ABOUT 640 NM W OF THE CAPE VERDE ISLANDS MOVING N AT 4 KT. ESTIMATED CENTRAL PRESSURE IS 975 MB. MAXIMUM SUSTAINED WIND SPEED IS 80 KT WITH GUSTS TO 100 KT. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. CLOUD PATTERN IS BECOMING ELONGATED DUE TO INCREASING SWLY SHEAR. SCATTERED MODERATE/STRONG CONVECTION IS FROM 16N-19N BETWEEN 34W-36W. SCATTERED MODERATE CONVECTION COVERS THE REMAINDER OF THE AREA FROM 16N-21N BETWEEN 32W-37W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 74W/75W S OF 19N MOVING W 10-15 KT. WAVE IS BEGINNING TO LAG THE DEEP LAYER MOISTURE AS INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS AT THE BASE OF AN UPPER TROUGH EXTENDING FROM AN UPPER LOW N OF PUERTO RICO AND WITHIN AN AREA OF LOW LEVEL DRY AIR. THUS NO ASSOCIATED SHOWERS/CONVECTION. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N12W 8N22W 13N31W 11N41W 12N48W 10N56W 10N62W. SCATTERED STRONG CONVECTION IS WITHIN 60 NM OF LINE FROM 13N18W TO 15N17W INCLUDING DAKAR IN SENEGAL W AFRICA. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-15N BETWEEN 39W-41W. CLUSTERS OF SIMILAR CONVECTION ARE FROM 8N-11N BETWEEN 37W-57W. SMALL CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 5N-13N BETWEEN 18W-23W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A 1010 MB LOW SURFACE LOW HAS DEVELOPED INLAND JUST W OF MATAMOROS MEXICO WITH A SURFACE TROUGH EXTENDING FROM NEAR MATAGORDA BAY TEXAS THROUGH THE SURFACE LOW TO NEAR TAMPICO MEXICO. A SECOND SURFACE IS OVER THE SE GULF EXTENDING FROM 23N87W NE ALONG 26N83W ACROSS THE FLORIDA PENINSULA NEAR NAPLES INTO THE W ATLC NEAR FORT LAUDERDALE. AT THE UPPER LEVELS...AN UPPER TROUGH IS OVER TEXAS AND THE N PORTION OF MEXICO INDUCING A SHARP UPPER RIDGE ALONG THE MEXICO/TEXAS COAST WITH A SECOND UPPER TROUGH OVER THE CAROLINAS S TO OVER NE FLORIDA. THIS IS CREATING A VERY DIFFLUENT ALOFT ENVIRONMENT ACROSS THE ENTIRE GULF AND COUPLED WITH THE BROAD AREA OF DEEP LAYERED MOISTURE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY IS ENHANCING SCATTERED/NUMEROUS SHOWERS WITH SCATTERED THUNDERSTORMS OVER MOST OF THE AREA. THE ONLY EXCEPTION IS IN THE SW GULF AND THE BAY OF CAMPECHE S OF 22N WHERE ONLY HIGH DEBRIS CLOUDS ARE FOUND. CARIBBEAN SEA... AN UPPER TROUGH COVERS THE W CARIBBEAN EXTENDING FROM W PANAMA TO NEAR THE CAYMAN ISLANDS AS WELL AS DEEP LAYERED MOISTURE AS INDICATED BY THE TOTAL PERCEPTIBLE WATER IMAGERY AND WITH DIFFLUENCE ALOFT OVER THE SE GULF OF MEXICO ARE GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND OVER CUBA AND IN THE CARIBBEAN WATERS N OF 21N. AN AREA OF ISOLATED/SCATTERED SHOWERS ARE OVER THE SW CARIBBEAN S OF 15N BETWEEN 77W-82W. A SECOND UPPER TROUGH COVERS THE NE CARIBBEAN EXTENDING FROM THE W/CENTRAL ATLC ACROSS HISPANIOLA AND PUERTO RICO TO 15N BETWEEN 65W-75W. THE ITCZ EXTENDS ACROSS THE N PORTION OF SOUTH AMERICA AND PANAMA INTO THE E PACIFIC REGION GENERATING SCATTERED SHOWERS/THUNDERSTORMS INLAND AND WITHIN 45 NM ALONG THE COAST OF PANAMA E OF 80W. OTHERWISE THE REMAINDER OF THE CARIBBEAN IS FAIRLY TRANQUIL THIS EVENING. ATLANTIC OCEAN... AS OF 2100 UTC...A SURFACE TROUGH EXTENDS THROUGH 32N72W SW ALONG 27N77W ACROSS THE FLORIDA PENINSULA INTO THE GULF OF MEXICO NEAR FORT LAUDERDALE TO NAPLES. AN UPPER TROUGH SUPPORTING THE SURFACE TROUGH COVERS THE CAROLINAS S TO OVER NE FLORIDA AND INTO THE W ATLC N OF 27N W OF 75W. A NARROW UPPER RIDGE EXTENDS FROM THE N BAHAMA ISLANDS NE TO NEAR BERMUDA PROVIDING DIFFLUENCE ALOFT TO GENERATE A BROAD AREA OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS SE OF THE SURFACE TROUGH AND W OF A LINE FROM 30N67W 25N67W TO E CUBA NEAR 20N74W. A WEAK 1015 MB SURFACE LOW IS N OF PUERTO RICO NEAR 22N66W. THE LOW IS SUPPORTED BY AN UPPER LEVEL TROUGH THAT COVERS THE W ATLC S OF 28N INTO THE NE CARIBBEAN BETWEEN 60W-70W AND CENTERED NEAR 25N66W. A WEAK 1020 MB SURFACE HIGH IS NNE OF THE SURFACE LOW CENTERED NEAR 29N63W. FARTHER E...AN UPPER TROUGH ENTERS THE CENTRAL ATLC NEAR 32N35W TO A LARGE RATHER DRY UPPER LOW NEAR 21N48W SUPPORTING A SURFACE TROUGH EXTENDING FROM 31N43W TO 25N55W WITH ISOLATED SHOWERS WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH. THIS UPPER LOW IS ALSO SUPPORTING A SECOND SURFACE TROUGH THAT EXTENDS FROM 25N46W S TO 14N48W WITH POSSIBLE ISOLATED SHOWERS WITHIN 90 NM E OF THE SURFACE TROUGH N OF 20N. A SURFACE RIDGE IS OVER THE E ATLC EXTENDING N OF 25N FROM 20W-40W. A WEAK 1015 MB LOW IS N OF THE CANARY ISLANDS NEAR 31N16W SUPPORTED BY AN UPPER TROUGH THAT EXTENDS FROM INLAND OVER MOROCCO SW TO OVER THE CANARY ISLANDS. $$ WALLACE