000 AXNT20 KNHC 310611 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... HURRICANE GUSTAV IS CENTERED NEAR 23.1N 83.8W AT 31/0300 UTC OR OVER THE SOUTHEASTERN GULF OF MEXICO ABOUT 90 MILES...145 KM...WEST OF HAVANA CUBA AND ABOUT 530 MILES...850 KM...SOUTHEAST OF THE MOUTH OF THE MISSISSIPPI RIVER. MOVING NW AT 13 KT. THE MINIMUM CENTRAL IS 948 MB. MAXIMUM SUSTAINED WIND SPEED IS 120 KT WITH GUSTS TO 150 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. GUSTAV IS AN EXTREMELY DANGEROUS CATEGORY FOUR 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 WITHIN 90 NM OF THE CENTER. SCATTERED MODERATE CONVECTION COVERS THE REMAINDER OF THE AREA FROM 22N-26N BETWEEN 79W-86W...TO INCLUDE OUTER RAINBANDS ACROSS THE FLORIDA PENINSULA AND ERN GULF OF MEXICO. TROPICAL STORM HANNA IS CENTERED NEAR 22.9N 67.8W AT 31/0300 UTC OR ABOUT 230 MILES...375 KM...EAST-NORTHEAST OF GRAND TURK ISLAND. MOVING WNW AT 7 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. HANNA CONTINUES TO EXPERIENCE WLY SHEAR. MUCH OF THE CONVECTION IS LOCATED E OF THE CENTER. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 20N-26N BETWEEN 64W-67W. SCATTERED MODERATE CONVECTION IS ALSO FROM 24N-26N BETWEEN 67W-69W. TROPICAL WAVE IS ALONG 28W S OF 20N WITH A 1009 MB SURFACE LOW ALONG THE WAVE NEAR 15N. 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. SCATTERED MODERATE CONVECTION IS FROM 16N-18N BETWEEN 26W-29W. SCATTERED SHOWERS COVER THE REMAINDER OF THE AREA FROM 14N-22N BETWEEN 23W-32W. 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 48W S OF 25N MOVING WNW NEAR 10 KT. A 1009 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 21N48W. 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 19N-24N BETWEEN 43W-48W. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 17N16W 15N27W 9N32W 11N50W 10N61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE W AFRICAN COAST FROM 7N-11N BETWEEN 13W-17W. SCATTERED MODERATE CONVECTION IS FURTHER N FROM 14N-17N BETWEEN 15W-19W. ISOLATED MODERATE CONVECTION IS FROM 6N-10N BETWEEN 28W-40W. ...DISCUSSION... GULF OF MEXICO... HURRICANE GUSTAV IS THE MAIN TOPIC FOR THE SE GULF OF MEXICO... STRAITS OF FLORIDA...AND FLORIDA PENINSULA...AS IT CONTINUES TRACKING NW TOWARDS THE NORTH CENTRAL GULF. 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 AROUND MONDAY AFTERNOON. CARIBBEAN SEA... HURRICANE GUSTAV IS MOVING AWAY FROM CUBA BUT CONVECTION REMAINS OVER CUBA W OF 78W. SEE SPECIAL FEATURES ABOVE. 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 INLAND OVER HONDURAS AND NICARAGUA FROM 11N-16N BETWEEN 85W-90W. 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