000 AXNT20 KNHC 230600 TWDAT TROPICAL WEATHER DISCUSSION... NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT AUG 23 2008 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 0515 UTC. ...SPECIAL FEATURES... TROPICAL STORM FAY HAS DRENCHED FLORIDA FOR FIVE DAYS IN A ROW CAUSING TORRENTIAL RAINS AND WIDESPREAD FLOODING. ISOLATED STORM TOTAL RAINFALL AMOUNTS OF 20 TO 30 INCHES HAVE BEEN OBSERVED WITH FAY ACROSS PORTIONS OF THE EAST-CENTRAL COAST OF FLORIDA. AT 23/0600 UTC FAY IS CENTERED OVER WATER NEAR 29.8N 84.7W OF JUST SOUTH OF CARRABELLE FLORIDA. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. THE CENTER OF FAY CROSSED THE COAST OF THE BIG BEND AREA OF FLORIDA NEAR KEATON BEACH AT ABOUT 2200 UTC...EMERGING OVER APALACHEE BAY IN THE EXTREME NORTHEASTERN GULF OF MEXICO. THE CENTER OF FAY WILL BE NEAR OR OVER WATER DURING THE NEXT 48 HOURS OR SO...WHILE ATMOSPHERIC CONDITIONS REMAIN CONDUCIVE TO SUPPORT A TROPICAL STORM. FAY WILL BE MOVING RATHER SLOWLY DURING THE NEXT SEVERAL DAYS...POSING A SIGNIFICANT HEAVY RAINFALL AND FLOOD HAZARD TO A VERY LARGE AREA. FAY IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 5 TO 10 INCHES ACROSS THE NORTHERN FLORIDA PENINSULA...THE FLORIDA PANHANDLE... SOUTHERN GEORGIA...SOUTHERN ALABAMA...AND SOUTHERN MISSISSIPPI...WITH ISOLATED MAXIMUM AMOUNTS OF 15 INCHES POSSIBLE. ADDITIONAL RAIN ACCUMULATIONS OF 1 TO 2 INCHES ARE POSSIBLE OVER CENTRAL AND SOUTHERN FLORIDA IN OUTER RAIN BANDS ASSOCIATED WITH FAY. ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE POSSIBLE OVER COASTAL SOUTHERN SOUTH CAROLINA. PRESENTLY DOPPLER RADAR SHOWS RAINBANDS ASSOCIATED WITH THE CIRCULATION OF FAY OVER N FLORIDA...THE FLORIDA PANHANDLE...S GEORGIA AND SE ALABAMA. A BAND OF SHOWERS WITH EMBEDDED TSTMS IS ALSO OVER SOUTHERN SOUTH CAROLINA. ...TROPICAL WAVES... A TROPICAL WAVE HAS EMERGED OFF THE COAST OF W AFRICA AND IS ALONG 21W S OF 19N MOVING W AT 10-15 KT. THE DAKAR VERTICAL SOUNDING THAT SHOWED SE WINDS AT LOW LEVELS AND THE HOVMOLLER DIAGRAM OVER W AFRICA HELPED LOCATE THE WAVE. IN ADDITION...A CYCLONIC TURNING IS SEEN ALONG THE WAVE AXIS NEAR 13N. SCATTERED MODERATE CONVECTION IS AHEAD OF THE WAVE LINE AND WITHIN 200 NM OF THE SOUTHERN CAPE VERDE ISLANDS. A TROPICAL WAVE IS ALONG 43W/44W S OF 20N. SCATTERED MODERATE CONVECTION IS NOTED NEAR THE NORTHERN END OF THE WAVE AXIS FROM 18N-21N BETWEEN 43W-46W. SIGNIFICANT DEVELOPMENT OF THIS SYSTEM IS UNLIKELY DURING THE NEXT COUPLE OF DAYS AS THE WAVE MOVES WESTWARD AT ABOUT 15 KT. A 1009 MB AREA OF LOW PRESSURE IS LOCATED NEAR 11N58W OR A COUPLE HUNDRED MILES EAST OF THE WINDWARD ISLANDS. THIS LOW IS PRODUCING A SMALL AREA OF SHOWERS AND THUNDERSTORMS. GRADUAL DEVELOPMENT OF THIS SYSTEM IS POSSIBLE DURING THE NEXT COUPLE OF DAYS AS IT MOVES GENERALLY WESTWARD AT 10 TO 15 MPH. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINS AND GUSTY WINDS ARE EXPECTED TO SPREAD OVER PORTIONS OF THE WINDWARD AND LEEWARD ISLANDS TODAY. A TROPICAL WAVE IS OVER THE E CARIBBEAN ALONG 62W S OF 16N MOVING W NEAR 15 KT. SCATTERED SHOWERS AND TSTMS ARE WITHIN 80-100 NM EITHER SIDE OF THE WAVE AXIS. CURRENTLY THE WINDWARD ISLANDS ARE REPORTING MAINLY LIGHT SHOWERS...BUT THE CHANGE OF RAIN WILL INCREASE TODAY AS THE LOW MENTIONED ABOVE MOVES ACROSS THE AREA. A TROPICAL WAVE IS OVER CENTRAL AMERICA AND THE EPAC ALONG 86W S OF 15N MOVING W 15-20 KT. MOST OF THE STRONG CONVECTION ASSOCIATED WITH THE WAVE IS ON THE PACIFIC SIDE. SCATTERED MODERATE CONVECTION IS NEAR THE COSTA RICA/PANAMA BORDER. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 12N16W 10N25W 14N35W 11N57W. BESIDES THE CONVECTION MENTIONED ON THE TROPICAL WAVE SECTION...A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION IS INLAND OVER WEST AFRICA APPROACHING THE COASTLINE. SCATTERED MODERATE CONVECTION IS NEAR 6N38W. SIMILAR CONVECTION IS OVER THE GUYANAS. ...DISCUSSION... GULF OF MEXICO... T.S. FAY REMAINS THE MAIN FEATURE OF INTEREST OVER THE GULF REGION AND THE STATE OF FLORIDA. SEE SPECIAL FEATURES FOR DETAILS. A WEAK RIDGE DOMINATES THE WESTERN HALF OF THE GULF WHILE THE EASTERN HALF IS UNDER THE INFLUENCE OF THE OVERALL CIRCULATION OF FAY GIVING THE AREA NW TO W WINDS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS OVER THE DEEP SOUTH AND NE MEXICO LIKELY DUE TO UPPER DIFFLUENCE BETWEEN AN UPPER-LEVEL LOW SPINNING OVER THE STATE OF CHIHUAHUA MEXICO AND AN UPPER-LEVEL HIGH OVER CENTRAL MEXICO. THIS HIGH DOMINATES THE WESTERN GULF. AN INVERTED TROUGH IS OVER THE CENTRAL GULF EXTENDING FROM AN UPPER LOW NEAR 25N87W TO THE E PORTION OF THE BAY OF CAMPECHE. ANOTHER UPPER-LEVEL HIGH CENTERED OVER WESTERN CUBA COVERS THE SE GULF. CARIBBEAN SEA... THE ATLANTIC RIDGE EXTENDS OVER THE GREATER ANTILLES PRODUCING MODERATE ELY TRADE WINDS. AN INVERTED UPPER TROUGH EXTENDS FROM THE MONA PASSAGE TO THE SW CARIBBEAN SEPARATING AN UPPER RIDGE ANCHORED OVER WRN CUBA AND THE FLORIDA STRAITS AND A SECOND UPPER RIDGE ANCHORED OVER THE FAR SE CARIBBEAN. THIS TROUGH SEEMS TO BE ENHANCING SOME SHOWER ACTIVITY OVER PUERTO RICO AND COASTAL WATERS. A TROPICAL WAVE IS OVER THE E CARIBBEAN. SEE ABOVE. MOISTURE FROM THIS FEATURE IS EXPECTED TO REACH THE UK/US VIRGIN ISLANDS AND PUERTO RICO LATE TODAY. ATLANTIC OCEAN... THE AZORES HIGH DOMINATES THE FORECAST AREA PRODUCING MOSTLY EASTERLY SURFACE FLOW OVER THE ATLANTIC PARTICULARLY FROM 20N-32N BETWEEN W AFRICA AND 60W. SHOWER ACTIVITY HAS DIMINISHED OVER THE W ATLC AS FAY CONTINUES TO MOVE WWD OVER THE EXTREME NE GULF OF MEXICO. IN THE UPPER LEVELS...AN UPPER-LEVEL HIGH SITUATED OVER E CUBA EXTENDS A RIDGE NWD OVER THE BAHAMAS AND PART OF THE W ATLC. AN UPPER-LEVEL TROUGH ENTERS THE AREA NEAR 32N68W THEN CONTINUES MAINLY S TO ANOTHER UPPER LOW LOCATED N OF PUERTO RICO NEAR 21N65W. UPPER DIFFLUENCE AHEAD OF THE TROUGH IS GENERATING AN AREA OF SHOWERS WITH EMBEDDED TSTMS N OF 22N BETWEEN 60W-75W. AN EARLIER QSCAT PASS SHOWED SOME WIND SHIFT OVER THAT AREA. BASED ON CONVECTIVE ACTIVITY AND THE QSCAT PASS A SFC TROUGH WILL BE ADDED TO THE 0600 UTC MAP IN THAT REGION. AN UPPER LEVEL HIGH LOCATED NEAR 27N45W DOMINATES THE CENTRAL ATLC. A LARGE UPPER-LEVEL LOW IS OVER THE E ATLANTIC NEAR 29N25W. $$ GR