000 AXNT20 KNHC 112354 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 11 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... TROPICAL STORM FRED IS CENTERED NEAR 18.1N 34.6W AT 11/2100 UTC OR ABOUT 715 MILES...1150 KM...WEST-NORTHWEST OF THE CAPE VERDE ISLANDS DRIFTING NE AT 2 KT. LITTLE MOTION IS EXPECTED OVER THE NEXT COUPLE OF DAYS. ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO 60 KT WITH GUSTS TO 75 KT. FURTHER WEAKENING OF FRED IS EXPECTED. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED MODERATE/STRONG CONVECTION IS FROM 17N-21N BETWEEN 32W-36W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 21W S OF 20N MOVING W NEAR 15 KT. A 1010 MB LOW IS ALONG THE WAVE AXIS NEAR 12N. SATELLITE IMAGERY AND AN EARLIER QUIKSCAT PASS CONFIRMED THE LOCATION OF THE LOW CIRCULATION. ISOLATED MODERATE CONVECTION IS FROM 14N-17N BETWEEN 20W-25W. TROPICAL WAVE IS ALONG 81W S OF 19N MOVING W NEAR 18 KT. THE WAVE FOLLOWS A MAXIMUM IN DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. THE WAVE HAS MOVED UNDER MOIST SLY FLOW ALOFT AROUND AN UPPER LEVEL LOW S OF GUATEMALA WHICH HAS ENHANCED A LARGE CLUSTER OF SCATTERED MODERATE TO STRONG CONVECTION FROM 8N-14N BETWEEN 83W-88W. THE CONVECTION MAY BE MORE ASSOCIATED WITH UPPER LEVEL DIFFLUENT FLOW THAN SURFACE CONVERGENCE NEAR THE WAVE. WIDELY SCATTERED MODERATE CONVECTION IS ALSO CLOSER TO THE WAVE AXIS FROM 11N-15N BETWEEN 80W-83W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 7N26W 14N34W 11N50W 10N62W. BESIDES THE CONVECTION MENTIONED IN THE SPECIAL FEATURE SECTION AND THE TROPICAL WAVE SECTION...WIDELY SCATTERED MODERATE CONVECTION IS ALONG THE COAST OD WEST AFRICA FROM 12N-15N BETWEEN 16W-19W. ISOLATED MODERATE CONVECTION IS FROM 4N-9N BETWEEN 24W-29W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A SURFACE TROUGH IS OVER THE NW GULF OF MEXICO FROM 29N92W TO A 1010 MB SURFACE LOW IS ANALYZED OFF THE TEXAS COAST NEAR 29N93W TO 27N97W. THIS SYSTEM IS SUPPORTED BY AN UPPER LEVEL TROUGH FORMING OVER MEXICO AND TEXAS EXTENDING INTO THE FAR W CARIBBEAN. SURFACE CONVERGENCE NEAR THE SURFACE LOW AND TROUGH ALONG WITH UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER TROUGH AND AN UPPER LEVEL RIDGE DOMINATING THE CENTRAL GULF ARE SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE GULF N OF 22N. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE OVER THE NEXT 24 HOURS AS THE TROUGH MOVES NW. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE W CARIBBEAN. SEE ABOVE. FRESH TO STRONG TRADEWINDS ARE OVER THE CARIBBEAN AND CENTRAL AMERICA. CLUSTERS OF SCATTERED MODERATE TO STRONG CONVECTION ARE OVER CUBA...THE YUCATAN CHANNEL...AND THE YUCATAN PENINSULA N OF 20N BETWEEN 77W-89W. SIMILAR CONVECTION IS OVER N COLOMBIA FROM 8N-12N BETWEEN 73W-76W. SCATTERED SHOWERS ARE OVER PUERTO RICO AND HISPANIOLA. IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH IS OVER THE W CARIBBEAN W OF 80W WITH SIGNIFICANT UPPER LEVEL MOISTURE. WESTERLY UPPER LEVEL FLOW WITH STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE CARIBBEAN. EXPECT...CONTINUED CONVECTION OVER THE W CARIBBEAN AND CENTRAL AMERICA W OF 85W OVER THE NEXT 24 HOURS AS THE TROPICAL WAVE MOVES W. ATLANTIC OCEAN... A SURFACE TROUGH IS OFF THE COAST OF FLORIDA ALONG 32N72W 29N80W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE TROUGH AXIS S OF 30N. A 1020 MB HIGH IS OVER THE W ATLANTIC NEAR 29N64W. A COLD FRONT IS FURTHER E ALONG 32N41W 29N50W 32N60W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE FRONT. A 1020 MB HIGH IS OVER THE E ATLANTIC NEAR 38N20W. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS OVER THE W ATLANTIC N OF PUERTO RICO NEAR 24N65W. UPPER LEVEL DIFFLUENCE NW OF THE CENTER IS PRODUCING WIDELY SCATTERED MODERATE CONVECTION E OF THE BAHAMAS FROM 24N-29N BETWEEN 68W-74W. ANOTHER UPPER LEVEL LOW IS OVER THE CENTRAL ATLANTIC NEAR 21N44W PRODUCING SW SHEAR OVER T.S. FRED. A LARGE UPPER LEVEL HIGH IS OVER THE TROPICAL E ATLANTIC NEAR THE CAPE VERDE ISLANDS AT 19N21W. $$ FORMOSA