000 AXNT20 KNHC 290551 TWDAT TROPICAL WEATHER DISCUSSION... NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI AUG 29 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 0345 UTC. ...SPECIAL FEATURES... TROPICAL STORM GUSTAV IS CENTERED NEAR 17.9N 77.7W AT 29/0600 UTC OR ABOUT 52 NM WEST OF KINGSTON JAMAICA AND ABOUT 195 NM EAST-SOUTHEAST OF GRAND CAYMAN MOVING W AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 993 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 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. OUTFLOW FROM GUSTAV REMAINS GOOD IN ALL QUADRANTS. A TURN TOWARD THE WNW AND NW IS FORECAST DURING THE NEXT COUPLE OF DAYS WITH GUSTAV PASSING NEAR OR OVER W JAMAICA DURING THE NIGHT WHILE STRENGTHENING AND MOVE NEAR OR OVER THE CAYMAN ISLANDS FRI OR FRI NIGHT POSSIBLY AS A HURRICANE WHILE APPROACHING W CUBA ON SAT. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM 17N-20N BETWEEN 75W-78W INCLUDING MOST OF JAMAICA. SCATTERED MODERATE/ STRONG CONVECTION IS WITHIN 60 NM OF LINE FROM S OF HAITI NEAR 17N72W TO 16N79W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVERING A BROADER AREA FROM 14N-22N BETWEEN 70W-82W. GUSTAV IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS OF 6 TO 12 INCHES ACROSS 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. RAINFALL ACCUMULATIONS OF 2 TO 4 INCHES ARE POSSIBLE OVER SOUTHERN CUBA. RAINFALL WILL BE DIMINISHING OVER HAITI TONIGHT...WITH AN ADDITIONAL 1 TO 2 INCHES OF RAINFALL POSSIBLE. TROPICAL STORM HANNA IS CENTERED NEAR 21.1N 60.6W AT 29/0300 UTC OR ABOUT 225 NM NORTHEAST OF THE NORTHERN LEEWARD ISLANDS MOVING WEST-NORTHWEST AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC AND/OR THE PUBLIC ADVISORY MIATCPAT3/WTNT33 KNHC FOR MORE DETAILS. OUTFLOW FROM HANNA IS MAINLY TO THE E AND S MOSTLY DUE TO AN UPPER LOW JUST TO THE W. HANNA IS FORECAST TO GRADUALLY MOVE AWAY FROM THE NORTHERN LEEWARD ISLANDS AND BE LOCATED WELL TO THE NORTHEAST OF THE BAHAMAS DURING THE NEXT COUPLE OF DAYS. GRADUAL STRENGTHENING IS FORECAST DURING THE NEXT COUPLE OF DAYS AND HANNA COULD BECOME A HURRICANE BY SATURDAY. SCATTERED/NUMEROUS STRONG CONVECTION WITHIN 45/60 NM OF LINE FROM 17N61W 19N59W TO 21N60W WITH SCATTERED MODERATE/STRONG CONVECTION COVERING THE REMAINDER OF THE AREA FROM WITHIN 120 NM OF LINE FROM THE N LEEWARD ISLANDS NEAR 17N62W 20N58W TO 23N61W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG THE COAST OF W AFRICA ALONG 17W/18W S OF 17N MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS DEPICTED ON THE MIMIC-TPW ANIMATION WITH A BROAD MID LEVEL CYCLONIC ROTATION OBSERVED ON SATELLITE IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 12N-18N BETWEEN THE COAST OF W AFRICA TO 20W. TROPICAL WAVE IS ALONG 38W/39W FROM 12N TO 21N WITH A 1009 MB LOW ALONG THE WAVE AXIS NEAR 18N MOVING WNW NEAR 10 KT. HIGH AMPLITUDE WAVE IS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS DEPICTED ON THE MIMIC-TPW ANIMATION BUT WATER VAPOR IMAGERY SHOWERS MODERATE SUBSIDENCE OVER THE AREA S OF THE LOW. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 18N-21N BETWEEN 37W-43W. TROPICAL WAVE IS ALONG 54W/55W S OF 13N MOVING W NEAR 10 KT. THIS WAVE HAS LOST ITS INVERTED-V CURVATURE AND LACK DEEP LAYERED MOISTURE AND CONVECTION. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 10N19W 16N33W 10N52W. THE ITCZ HAS BEEN DISRUPTED BY THE TROPICAL WAVES AND T.S. HANNA. SCATTERED MODERATE CONVECTION IS FROM 9N-13N BETWEEN 30W-36W WITH CLUSTERS OF SIMILAR CONVECTION FROM 7N-12N BETWEEN 19W-30W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER TROUGH DOMINATES MOST OF THE GULF EXTENDING FROM AN UPPER LOW OVER WRN NORTH CAROLINA ACROSS THE FLORIDA PANHANDLE NEAR PANAMA CITY TO THE NW YUCATAN PENINSULA. UPPER RIDGE OVER MEXICO ARE PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 27N W OF 90W. VERY WEAK SURFACE RIDGE ENCOMPASSES THE N GULF. MODERATE SUBSIDENCE AND DRY AIR IS NOTED N OF 26N BETWEEN 85W-93W SUPPRESSING ANY SHOWER ACTIVITY KEEPING THE REMAINDER OF THE GULF TRANQUIL TONIGHT. CARIBBEAN SEA... THE MAIN CONCERN CONTINUES TO BE T.S. GUSTAV FOR THE N/CENTRAL CARIBBEAN AND ACTIVITY ASSOCIATED WITH T.S. HANNA FOR THE LEEWARD/VIRGIN ISLANDS TONIGHT...SEE SPECIAL FEATURES ABOVE. THE BROAD UPPER HIGH ASSOCIATED WITH GUSTAV IS ALSO DOMINATING MOST OF THE CARIBBEAN AS WELL. SCATTERED SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER NICARAGUA MOVING INTO THE CARIBBEAN WATERS FROM THE BORDER OF COSTA RICA TO 13N W OF 82W. THE ITCZ CROSSES THE N PORTION OF SOUTH AMERICA GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS WITHIN 45 NM ALONG THE COAST OF COLOMBIA TO PANAMA. THE ENTIRE CARIBBEAN IS EMBEDDED WITHIN DEEP LAYERED MOISTURE AS DEPICTED ON THE MIMIC-TPW ANIMATION...SO ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE OVER THE REMAINDER OF THE CARIBBEAN. ATLANTIC OCEAN... A CONCERN FOR THE THE ATLC NE OF THE LEEWARD/VIRGIN ISLANDS IS T.S. HANNA TONIGHT...SEE SPECIAL FEATURES ABOVE. AN UPPER HIGH IS CENTERED NEAR 30N69W WITH AN UPPER LOW TO THE S...N OF PUERTO RICO NEAR 23N66W ENCOMPASSING THE W ATLC. THE UPPER LOW IS PROVIDING UPPER LEVEL SHEAR FOR T.S. HANNA AND GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 21N-25N BETWEEN 63W-68W. A SURFACE TROUGH IS NE OF THE BAHAMAS EXTENDING FROM 28N70W TO 23N73W GENERATING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 75 NM OF THE TROUGH AXIS. A SHARP UPPER TROUGH IS IN THE CENTRAL ATLC EXTENDING ALONG 47W TO NEAR 22N INDUCING AN UPPER RIDGE TO THE W FROM NEAR T.S. HANNA NNE TO 32N54W. AN E/W UPPER RIDGE COVERS THE E ATLC ALONG 21N TO 40W. AT THE SURFACE...A BROAD SURFACE RIDGE REMAINS OVER THE ATLC N OF 25N E OF 55W ANCHORED BY A 1027 MB HIGH W OF THE AZORES. $$ WALLACE