000 AXNT20 KNHC 311202 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN AUG 31 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... HURRICANE GUSTAV IS CENTERED NEAR 24.7N 85.5W AT 31/1200 UTC OR ABOUT 325 MILES...605 KM...SOUTHEAST OF THE MOUTH OF THE MISSISSIPPI RIVER MOVING NW AT 16 KT. THE LATEST MINIMUM CENTRAL PRESSURE REPORTED BY THE AIR FORCE HURRICANE HUNTER IS 960 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH HIGHER GUSTS. 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. GUSTAV IS AN EXTREMELY DANGEROUS CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE. GUSTAV'S CENTER HAS TRAVERSED CUBA AND IS NOW IN THE GULF OF MEXICO. IT IS PRESENTLY STRENGTHENING AGAIN AFTER WEAKENING A BIT OVER W CUBA. OUTFLOW IS BEST N OF THE CENTER. UPPER LEVEL OUTFLOW WILL AGAIN BECOME MORE SYMMETRICAL AS GUSTAV MOVES AWAY FROM CUBA. NUMEROUS STRONG CONVECTION IS FROM 23N-25N BETWEEN 83W-86W. SCATTERED MODERATE CONVECTION COVERS THE REMAINDER OF THE AREA FROM 22N-28N BETWEEN 83W-87W...TO INCLUDE OUTER RAINBANDS ACROSS THE FLORIDA PENINSULA AND ERN GULF OF MEXICO. TROPICAL STORM HANNA IS CENTERED NEAR 23.2N 69.5W AT 31/1200 UTC OR ABOUT 135 MILES...250 KM...NORTHEAST OF GRAND TURK ISLAND MOVING WNW AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 999 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 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. HANNA CONTINUES TO EXPERIENCE WLY SHEAR. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 21N-25N BETWEEN 70W-72W...AND FROM 20N-24N BETWEEN 65W-69W. TROPICAL WAVE IS ALONG 31W S OF 21N WITH A 1007 MB SURFACE LOW ALONG THE WAVE NEAR 16N. THE SYSTEM IS MOVING W 10-15 KT. A BROAD MID LEVEL CYCLONIC ROTATION IS OBSERVED ON SATELLITE IMAGERY WITH ASSOCIATED CONVECTION MOSTLY LOCATED NORTH OF THE LOW. WIDELY SCATTERED MODERATE CONVECTION IS FROM 16N-19N BETWEEN 27W-33W. CONDITIONS APPEAR CONDUCIVE FOR DEVELOPMENT AND THIS SYSTEM COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 49W S OF 25N MOVING WNW NEAR 10 KT. A 1008 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 20N49W. AN INVERTED-V SATELLITE SIGNATURE IS OBSERVED WITH THIS SYSTEM WELL N OF THE ITCZ. SCATTERED MODERATE TO STRONG CONVECTION IS E OF THE WAVE AXIS FROM 17N-25N BETWEEN 44W-49W. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 14N17W 17N25W 16N31W 10N34W 12N50W 13N61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE W AFRICAN COAST FROM 7N-12N BETWEEN 13W-18W. SCATTERED MODERATE CONVECTION IS FURTHER N FROM 16N-17N BETWEEN 20W-22W. ISOLATED MODERATE CONVECTION IS FROM 6N-10N BETWEEN 28W-41W... AND FROM 10N-14N BETWEEN 24W-28W. ...DISCUSSION... GULF OF MEXICO... HURRICANE GUSTAV IS THE MAIN TOPIC FOR THE GULF OF MEXICO...AS IT CONTINUES TO TRACK NW TOWARDS THE NORTH CENTRAL GULF WHERE HURRICANE WARNINGS HAVE ALREADY BEEN ISSUED. SEE SPECIAL FEATURES ABOVE. OVERCAST SKIES ARE OVER THE E GULF E OF 90W. MOSTLY FAIR WEATHER IS OVER THE W GULF BETWEEN 90W-96W. IN THE UPPER LEVELS ...AN UPPER TROUGH IS OVER THE NW GULF OF MEXICO. UPPER LEVEL DIFFLUENCE FROM THIS TROUGH IS GENERATING CLUSTERS OF SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE FAR WRN GULF AND MEXICO W OF 96W. EXPECT GUSTAV TO MAKE LANDFALL AS A MAJOR HURRICANE OVER THE NORTH CENTRAL GULF MONDAY AFTERNOON. CARIBBEAN SEA... HURRICANE GUSTAV IS MOVING AWAY FROM CUBA WHERE HEAVY PRECIPITATION IS ENDING. SEE SPECIAL FEATURES ABOVE. ELSEWHERE...SCATTERED SHOWERS REMAIN OVER THE NRN LEEWARD ISLANDS AND THE VIRGIN ISLANDS ASSOCIATED WITH OUTER RAINBANDS OF T.S. HANNA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALONG THE COAST OF N COLOMBIA FROM 11N-13N BETWEEN 73W-76W. SIMILAR CONVECTION IS ALONG THE COAST OF PANAMA FROM 9N-12N BETWEEN 79W-84W. IN THE UPPER LEVELS...MOSTLY EASTERLY FLOW IS NOTED OVER THE CARIBBEAN MOSTLY DUE TO OUTFLOW FROM GUSTAV AND HANNA. SUBSIDENCE AND DRY AIR IS OVER THE WINDWARD ISLANDS. CONSIDERABLE UPPER LEVEL MOISTURE IS OVER THE REMAINDER OF THE CARIBBEAN AND CENTRAL AMERICA. ATLANTIC OCEAN... A 1025 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 34N44W. T.S. HANNA AND THE TROPICAL WAVES ARE THE MAIN FEATURES IN THE TROPICAL ATLANTIC. SEE ABOVE. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS IN THE VICINITY OF HANNA NEAR 23N68W INFLUENCING THE STORM. ANOTHER UPPER LEVEL LOW IS OVER THE CENTRAL ATLANTIC NEAR 26N48W. AN UPPER LEVEL HIGH IS OVER THE E ATLANTIC NEAR 23N34W.` $$ FORMOSA