000 AXNT20 KNHC 272358 TWDAT TROPICAL WEATHER DISCUSSION... NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 27 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... TROPICAL STORM GUSTAV IS CENTERED NEAR 19.0N 75.0W AT 28/0000 UTC OR ABOUT 56 NM SOUTH OF GUANTANAMO CUBA MOVING WEST AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND/OR THE PUBLIC ADVISORY MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. A WNW TO W TRACK IS FORECAST DURING THE NEXT DAY OR TWO WITH A GRADUAL INCREASE IN FORWARD SPEED. ON THE FORECAST TRACK GUSTAV SHOULD PASS BETWEEN JAMAICA AND THE SE COAST OF CUBA ON THU. GRADUAL STRENGTHENING IS FORECAST AND GUSTAV COULD REGAIN HURRICANE STRENGTH ON THU AS IT MOVES FARTHER OUT OVER THE WARMER NRN CARIBBEAN SEA WATERS. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM OF THE CENTER IN THE SOUTHERN SEMICIRCLE. SIMILAR CONVECTION IS ASSOCIATED WITH AN OUTER BAND SOUTH OF JAMAICA FROM 15N-18N BETWEEN 75W-79W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-20N BETWEEN 71W-75W. GUSTAV IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 6 TO 12 INCHES OVER HAITI... EASTERN CUBA... JAMAICA...AND THE CAYMAN ISLANDS...WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 25 INCHES POSSIBLE. THESE RAINS WILL LIKELY PRODUCE LIFE-THREATENING FLASH FLOODS AND MUD SLIDES. A 1009 MB SURFACE LOW NEAR 19N57W IS SLOWLY DRIFTING WNW AND REMAINS FAVORABLE FOR DEVELOPMENT OVER THE NEXT DAY OR TWO. AN UPPER LEVEL RIDGE EXTENDS FROM THE ERN CARIBBEAN OUT INTO THE CENTRAL ATLC AND IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED MODERATE TO STRONG CONVECTION FROM 18N-21N BETWEEN 53W-59W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 34W S OF 21N MOVING W 15-20 KT. A 1009 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 16N WITH A BROAD AREA OF DEEP LAYERED MOISTURE EVIDENT ON SATELLITE IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 17N-19N BETWEEN 31W-33W WITH SCATTERED SHOWERS FROM 16N-21N BETWEEN 31W-39W. TROPICAL WAVE IS ALONG 48W S OF 17N MOVING W NEAR 20 KT. THIS WAVE EXHIBITS A LOW AMPLITUDE AND IS EMBEDDED WITHIN SOME RATHER DRY AIR. NO ASSOCIATED SHOWERS/DEEP CONVECTION. TROPICAL WAVE IN THE SW CARIBBEAN IS ALONG 81W S OF 13N MOVING W NEAR 20 KT. ALTHOUGH THIS WAVE REMAINS EMBEDDED WITHIN DEEP LAYERED MOISTURE AND THE ITCZ...SCATTERED MODERATE TO STRONG CONVECTION IS ACROSS INLAND WRN PANAMA AND COSTA RICA. TROPICAL WAVE IN THE GULF OF MEXICO IS ALONG 97W S OF 20N MOVING W 15-20 KT. WAVE IS MOSTLY OVER S MEXICO AND THE E PACIFIC REGION PRODUCING SCATTERED MODERATE TO STRONG CONVECTION FROM 14N-18N BETWEEN 94W-97W. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 17N16W 16N25W 12N32W 10N36W 8N46W 7N50W 7N59W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 8N-14N BETWEEN 16W-21W. SCATTERED MODERATE CONVECTION IS WITHIN 90 NM OF THE AXIS BETWEEN 26W-33W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER TROUGH IS ACROSS THE CENTRAL AND WRN GULF OF MEXICO WITH AN UPPER HIGH REMAINING ANCHORED IN THE FLORIDA STRAITS NEAR 23N81W COVERING THE ERN GULF AND THE FLORIDA PENINSULA INTO THE W ATLC. UPPER DIFFLUENCE EAST OF THIS TROUGH IS GENERATING MULTILAYERED CLOUDINESS AND A FEW ISOLATED SHOWERS WITHIN 90 NM OF A LINE FROM APALACHICOLA BAY FLORIDA TO NEAR 25N92W. A CLUSTER OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO NOTED ACROSS SERN LOUISIANA DUE TO THE UPPER TROUGH. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE SRN FLORIDA PENINSULA IN ASSOCIATION WITH THE UPPER DIFFLUENT PATTERN IN PLACE OVER THE REGION. WITH THE TROPICAL WAVE AND AN UPPER RIDGE ACROSS SRN MEXICO...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE YUCATAN PENINSULA AND SRN MEXICO. AT THE SURFACE...A WEAK 1015 MB HIGH PRESSURE IS CENTERED NEAR 27N86W AND IS KEEPING THE REMAINDER OF THE SE GULF WITH TRANQUIL WEATHER. CARIBBEAN SEA... THE MAIN CONCERN FOR THE CARIBBEAN IS T.S. GUSTAV BETWEEN HAITI AND CUBA...SEE SPECIAL FEATURES ABOVE. AN UPPER HIGH CENTERED OVER THE FLORIDA STRAITS COVERS THE NW CARIBBEAN AND IS PROVIDING UPPER LEVEL DIFFLUENCE TO PRODUCE CLUSTERS OF SCATTERED SHOWERS/THUNDERSTORMS ALONG THE SRN CUBA COASTLINE WITHIN 90 NM. THIS UPPER RIDGE IS KEEPING THE REMAINDER OF THE NW CARIBBEAN RELATIVELY CLEAR THIS EVENING. CLUSTERS OF SCATTERED SHOWERS AND THUNDERSTORMS ASSOCIATED WITH T.S. GUSTAV ARE ACROSS THE CENTRAL CARIBBEAN SEA FROM 14N-20N BETWEEN 70W-79W. AN UPPER LEVEL RIDGE IS ACROSS THE ERN CARIBBEAN NEAR 16N67W AND IS PROVIDING UPPER DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE MONA PASSAGE AND PUERTO RICO EXTENDING SOUTHEASTWARD TO ACROSS THE LESSER ANTILLES N OF SAINT LUCIA AND EAST OF 64W. ATLANTIC OCEAN... AN UPPER RIDGE ANCHORED IN THE FLORIDA STRAITS NEAR 23N81W COVERS THE W ATLC W OF 69W. A BROAD UPPER TROUGH ENCOMPASSES THE REMAINDER OF THE W ATLC FROM 58W-69W WITH AN EMBEDDED UPPER LOW N OF PUERTO RICO NEAR 22N65W GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM 21N TO OVER THE ERN GREATER ANTILLES BETWEEN 64W-70W INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. A SURFACE TROUGH IS ANALYZED ALONG 27N63W TO 21N66W GENERATING ISOLATED SHOWERS FROM 21N-25N BETWEEN 63W-68W. AN UPPER RIDGE EXTENDS FROM THE ERN CARIBBEAN TO NEAR 19N50W WITH A 1009 MB SURFACE LOW NEAR 19N57W AND COUPLED WITH THE UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED MODERATE TO STRONG CONVECTION FROM 18N-21N BETWEEN 53W-59W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION ALSO EXTENDS S-SE FROM THE LOW FROM 14N-20N BETWEEN 53W-56W. A SECOND BUT BENIGN UPPER LOW COVERS THE E/CENTRAL ATLC CENTERED NEAR 31N43W EXTENDING S TO 22N. AN UPPER RIDGE COVERS THE REMAINDER OF THE ERN ATLC E OF 38W ANCHORED ON AN UPPER HIGH CENTERED OVER WESTERN SAHARA. BROAD SURFACE RIDGE REMAINS OVER THE ATLC N OF 25N E OF 52W ANCHORED BY A 1030 MB HIGH N OF THE AZORES. A WEAK SURFACE RIDGE EXTENDS SW FROM BERMUDA NEAR 30N70W TO OVER THE NW BAHAMAS. $$ HUFFMAN