000 WTNT42 KNHC 291503 TCDAT2 TROPICAL STORM GUSTAV DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072008 1100 AM EDT FRI AUG 29 2008 SINCE THE LAST AIRCRAFT FIX OVER WESTERN JAMAICA AT ABOUT 1100 UTC...WHICH INCLUDED A CENTRAL PRESSURE ESTIMATE OF 988 MB...GOES VISIBLE IMAGERY SUGGESTS THAT GUSTAV IS REGAINING ORGANIZATION NOW THAT ITS CENTER HAS EMERGED OVER WATER WEST OF JAMAICA. THE ADVISORY INTENSITY IS MAINTAINED AT 55 KT UNTIL WE RECEIVE NEW DATA FROM THE NEXT AIRCRAFT THIS AFTERNOON...ALTHOUGH IT IS POSSIBLE THAT GUSTAV IS ALREADY A LITTLE STRONGER. THE CYCLONE WILL HAVE MORE THAN 24 HOURS OVER THE VERY WARM WATERS OF THE NORTHWESTERN CARIBBEAN...AND BENEATH AN UPPER-LEVEL ANTICYCLONE...SO STRENGTHENING SEEMS IMMINENT AND COULD EVEN BE RAPID. THE RAPID INTENSIFICATION INDEX BASED ON THE SHIPS MODEL INDICATES A 28 PERCENT CHANCE OF AN INTENSITY INCREASE OF 30 KT OR MORE DURING THE NEXT 24 HOURS. SINCE THERE IS ABOUT 36 HOURS LEFT BEFORE GUSTAV CROSSES CUBA...THERE REMAINS SOME POSSIBILITY THAT GUSTAV COULD BECOME A MAJOR HURRICANE BEFORE CROSSING THE WESTERN PORTIONS OF THAT ISLAND. CONDITIONS OVER THE GULF OF MEXICO APPEAR TO SUPPORT A MAJOR HURRICANE AS WELL...ALTHOUGH WIND SHEAR COULD INCREASE A LITTLE. THE NEW OFFICIAL INTENSITY FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE AND IS A LITTLE HIGHER THAN THE INTENSITY CONSENSUS. GUSTAV IS MOVING AT ABOUT 295/7 BUT IS IN THE PROCESS OF TURNING TO THE RIGHT IN RESPONSE TO THE RIDGE TO ITS NORTH...AND IS HEADED FOR A WEAKNESS IN THE RIDGE THAT IS FORECAST BY ALL MODELS TO DEVELOP OVER THE EASTERN GULF OF MEXICO DURING THE NEXT COUPLE OF DAYS. THE GUIDANCE IS IN VERY GOOD AGREEMENT ON A PATH OVER THE WESTERN PORTIONS OF CUBA IN ROUGHLY 36 HOURS...FOLLOWED BY A TRACK INTO THE SOUTH-CENTRAL GULF OF MEXICO. THEREAFTER...THE MODELS DIVERGE TREMENDOUSLY OVER THE NORTHERN GULF DUE TO DIFFERENCES IN HOW THEY HANDLE THE HIGH MOVING EASTWARD ACROSS THE GREAT LAKES REGION. THE MODELS THAT SHOW A SLOWER AND MORE WESTWARD MOTION ACROSS THE NORTHERN GULF SHOW A LITTLE MORE RIDGING EXTENDING SOUTHWESTWARD FROM THE GREAT LAKES HIGH...WHILE THOSE THAT ARE FASTER AND STRAIGHT NORTHWESTWARD TOWARD THE NORTH-CENTRAL GULF COAST SHOW LESS OF THAT RIDGING. THE NEW OFFICIAL TRACK FORECAST IS ADJUSTED ONLY SLIGHTLY RIGHT OF THE PREVIOUS ADVISORY AND THE CONSENSUS...GIVING RESPECT TO THE NWS MODELS GFS...GFDL...AND HWRF...WHICH ALSO SEEM TO DEPICT A SLIGHTLY DEEPER SYSTEM THAT WE EXPECT GUSTAV TO BE. NEEDLESS TO SAY...DUE TO THE MODEL SPREAD THE TRACK FORECAST IS RATHER UNCERTAIN...AND FINAL LANDFALL REMAINS POSSIBLE THROUGHOUT THE NORTHERN GULF COAST. FORECAST POSITIONS AND MAX WINDS INITIAL 29/1500Z 18.6N 78.8W 55 KT 12HR VT 30/0000Z 19.3N 80.0W 70 KT 24HR VT 30/1200Z 20.8N 81.8W 80 KT 36HR VT 31/0000Z 22.6N 83.8W 95 KT...OVER WESTERN CUBA 48HR VT 31/1200Z 24.3N 85.7W 105 KT 72HR VT 01/1200Z 27.5N 89.0W 105 KT 96HR VT 02/1200Z 29.5N 91.0W 100 KT...INLAND 120HR VT 03/1200Z 31.0N 93.0W 60 KT...INLAND $$ FORECASTER KNABB