000 AXNT20 KNHC 210008 TWDAT TROPICAL WEATHER DISCUSSION... NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... FAY IS NOW OVER WATER AND SLIGHTLY STRONGER. THE MAIN THREAT CONTINUES TO BE THE TORRENTIAL RAINS ALONG ITS PATH. AT 21/0000...TROPICAL STORM FAY IS CENTERED NEAR 29.0N 80.3W JUST OFF THE EAST COAST OF CENTRAL FLORIDA AND ABOUT 40 MILES...75 KM...EAST-SOUTHEAST OF DAYTONA BEACH FLORIDA. ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH HIGHER GUSTS. PLEASE SEE THE LATEST NHC THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC AND PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC FOR MORE DETAILS. FAY HAS BEEN NEARLY STATIONARY DURING THE PAST FEW HOURS. THE MID-LEVEL RIDGE DEVELOPING NORTH OF FAY IS BLOCKING ITS NORTHWARD PROGRESSION AND THE STORM SHOULD SOON BEGIN TO MOVE VERY SLOWLY TOWARD THE NORTHWEST AND THE WEST-NORTHWEST. ON THIS TRACK...FAY IS FORECAST TO MOVE VERY SLOWLY ACROSS NORTHERN FLORIDA ON THURSDAY. THERE ARE NUMEROUS RAINBANDS SPIRALING AROUND FAY'S CENTER DRENCHING PORTIONS OF FLORIDA. SOME OF THESE BANDS CONTINUES TO AFFECT SOUTH FLORIDA WITH HEAVY SHOWERS AT TIME. THE HEAVIEST RAINBANDS ARE CURRENTLY OVER THE ATLANTIC COASTAL WATERS OF CENTRAL FLORIDA AS NOTED ON DOPPLER RADAR. FAY IS EXPECTED TO PRODUCE ADDITIONAL RAINFALL ACCUMULATIONS OF 5 TO 10 INCHES OVER EAST-CENTRAL AND NORTHEASTERN FLORIDA...WITH 3 TO 6 INCHES OVER SOUTHEASTERN GEORGIA. ISOLATED STORM TOTAL AMOUNTS OF 30 INCHES ARE POSSIBLE IN FLORIDA. ACCUMULATIONS OF 3 TO 5 INCHES ARE POSSIBLE IN THE NORTHWESTERN BAHAMAS. ...TROPICAL WAVES... A TROPICAL WAVE IS IN THE CENTRAL ATLC ALONG 52W S OF 18N MOVING W 10-15 KT. NO ASSOCIATED DEEP CONVECTION IS OBSERVED. THE WAVE HAS LEFT BEHIND A 1008 MB SFC LOW. THIS SYSTEM HAS CHANGED LITTLE DURING THE DAY...AND ANY DEVELOPMENT IS EXPECTED TO BE SLOW TO OCCUR DURING THE NEXT COUPLE OF DAYS. THE GFS MODEL NOW MOVES THE LOW FASTER THAN THE PREVIOUS DAYS. MOISTURE FROM THIS TROPICAL WAVE IS FORECAST TO REACH THE NORTHERN LEEWARD ISLANDS THU NIGHT INTO FRI...AND AFFECT THE VIRGIN ISLANDS AND PUERTO RICO FRIDAY NIGHT THROUGH SATURDAY. A WEAK TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 72W AND EXTENDS FROM HAITI TO THE VENEZUELA/COLOMBIA BORDER. THE WAVE IS ENHANCING SOME SHOWER/TSTM ACTIVITY OVER DOMINICAN REPUBLIC WHILE CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER THE LAKE MARACAIBO AREA. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 16N16W 15N25W 11N33W 12N50W 9N60W. A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION IS MOVING OFF THE WEST AFRICAN COAST JUST N OF THE ITCZ AXIS. ANOTHER LARGE CLUSTER WITH SIMILAR CONVECTION COVERS THE AREA FROM 6N-11N BETWEEN 32W-36W. IN BETWEEN...THERE IS A 1009 MB LOW NEAR 14N26W GENERATING A SMALL AREA OF SHOWERS AND TSTMS WITHIN 70 NM SW QUADRANT. ...DISCUSSION... GULF OF MEXICO... RAINBANDS ASSOCIATED WITH THE OVERALL CIRCULATION OF FAY CONTINUES TO BRING MORE RAIN TO THE STATE OF FLORIDA AND THE E GULF. ONE OF THESE BAND IS APPROACHING THE TAMPA BAY AREA. OTHERS ARE FORMING OVER SOUTH FLORIDA. AN UPPER-LEVEL LOW REMAINS OVER NE TEXAS WITH TROUGHING EXTENDING INTO THE FAR NW GULF. MOIST ONSHORE WINDS COMBINED WITH THIS UPPER TROUGH ARE HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER THE NW CORNER OF THE GULF AND ALONG THE TEXAS COAST. A LINE OF SHOWERS AND TSTMS IS OVER THE YUCATAN PENINSULA AND A SFC TROUGH WAS ANALYZED IN THAT AREA AT 2100 UTC. A 1015 MB HIGH REMAINS OVER THE N-CENTRAL GULF NEAR 28N90W EXTENDING A RIDGE OVER THE W GULF WHERE SLY WINDS OF 10 TO 15 KT PREVAIL. CARIBBEAN SEA... AN UPPER-LEVEL HIGH CENTERED OVER WESTERN CUBA COVERS THE NW CARIBBEAN WITH THE RIDGE AXIS EXTENDING TO NRN BELIZE. THIS FEATURE IS SUPPORTING THE DEVELOPMENT OF SOME SHOWER ACTIVITY OVER PARTS OF CUBA...THE COASTAL WATERS OF THE CAYMAN ISLANDS AND JAMAICA. A SECOND UPPER-LEVEL RIDGE ANCHORED ON A HIGH NEAR 27N60W DOMINATES THE E CARIBBEAN. AN UPPER-LEVEL TROUGH THAT ENTERS THE BASIN THROUGH THE MONA PASSAGE SEPARATES THESE TWO UPPER HIGHS. THE ITCZ AXIS CONTINUES TO ENHANCE CONVECTION OVER PARTS OF COSTA RICA AND PANAMA. A SURGE IN THE TRADE WINDS PAIRED WITH UPPER DIFFLUENCE IS PRODUCING SOME SHOWER ACTIVITY OVER THE LESSER ANTILLES AND THE E CARIBBEAN. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. SEE ABOVE. THE REMAINDER OF THE AREA IS DOMINATED BY MODERATE TO STRONG SUBSIDENCE AND DRY STABLE AIR. ATLANTIC OCEAN... SPIRAL RAINBANDS ASSOCIATED WITH T.S. FAY ARE OVER THE W ATLC MAINLY W OF 78W. THERE ARE ALSO SOME SHOWER ACTIVITY N OF 25N W OF 70W DUE TO UPPER DIFFLUENCE BETWEEN THE BASE OF AN UPPER TROUGH AND THE UPPER HIGH ASSOCIATED WITH FAY. AN UPPER-LEVEL LOW IS NEAR 23N67W WITH A TROUGH EXTENDING SW INTO THE CARIBBEAN SEA THROUGH THE MONA PASSAGE. FURTHER EAST...A LARGE UPPER-LEVEL LOW CENTERED NEAR 21N50W IS SPINNING OVER THE CENTRAL ATLC. A TROUGH CONNECTS THIS LOW WITH A WEAKER UPPER LOW JUST NW OF THE MADEIRA ISLANDS NEAR 34N18W. BOTH OF THESE LOWS ARE BENIGN FEATURES. MODERATE SUBSIDENCE AND SOMEWHAT DRY STABLE AIR COVERS THE ATLC E OF 60W GIVING THE REMAINDER OF THE AREA MOSTLY FAIR WEATHER CONDITIONS. AT THE SURFACE...THE AZORES HIGH CONTINUES TO DOMINATE MOST OF THE ATLC N OF 20N E OF 60W. THIS ANTICYCLONE IS FORECAST BY THE COMPUTER MODELS TO SLIGHTLY STRENGTHEN DURING THE NEXT 24 HOURS OR SO PRODUCING A SWATH OF MODERATE TO STRONG TRADE WINDS ACROSS THE TROPICAL ATLC...PARTICULARLY FROM 16N-22N. $$ GR