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| #213929 (Received by flhurricane at: 5:07 PM 05.Sep.2008) TCDAT4 HURRICANE IKE DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092008 500 PM EDT FRI SEP 05 2008 AN AIR FORCE RECONNAISSANCE PLANE HAS PERFORMED THE FIRST PENETRATIONS ON IKE AND HAS CONFIRMED THE SATELLITE ESTIMATES. PEAK FLIGHT LEVEL WINDS OF 109 KT WERE RECORDED...ALONG WITH SFMR WINDS OF 94 KT...PLUS A DROPSONDE SUGGESTED WINDS OF AT LEAST 95 KT. A CONSENSUS OF ALL DATA SOURCES SUGGEST SUSTAINED WINDS OF AROUND 100 KT...SO THIS VALUE WILL BE THE INITIAL INTENSITY. SOME WEAKENING COULD OCCUR IN THE NEXT DAY OR SO DUE TO PERSISTENT NORTHERLY SHEAR. HOWEVER THIS SHEAR IS FORECAST TO DIMINISH BY LATE TOMORROW...AND SHOULD ALLOW SOME STRENGTHENING...PERHAPS RAPID...BY LATE IN THE WEEKEND. THE OFFICIAL FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE...SHOWING AN EXTREMELY DANGEROUS HURRICANE FOR THE NEXT SEVERAL DAYS. THIS FORECAST IS IN LINE WITH LGEM MODEL EARLY ON...AND IS A LITTLE LOWER THAN THE GFDL/HWRF THEREAFTER. A BIG UNCERTAINTY IN THE LONG RANGE INTENSITY FORECAST IS IKE'S POTENTIAL INTERACTION WITH CUBA OR FLORIDA...WHICH COULD WEAKEN THE HURRICANE MORE THAN SHOWN BELOW. AIRCRAFT AND SATELLITE FIXES SUGGEST A MOTION OF ABOUT 255/13. A GRADUAL BEND BACK TOWARD THE WEST IS FORECAST IN A DAY OR SO AS RIDGING TO THE NORTHWEST OF IKE WEAKENS SOMEWHAT. ALL MODELS SUGGEST SOME SORT OF WEAKNESS IN THE RIDGE NEAR FLORIDA IN A FEW DAYS BETWEEN A RIDGE OVER THE WESTERN ATLANTIC AND THE GULF OF MEXICO. THIS WEAKNESS MAY ALLOW A WEST-NORTHWEST OR NORTHWEST TURN OF THE HURRICANE. GENERALLY...THE MODELS THAT ARE SHOWING THE NORTHERNMOST TRACKS...SUCH AS THE GFS/NOGAPS...ARE THE ONES WEAKENING THE RIDGE TO THE NORTH FASTER. THE MODELS WITH THE SOUTHERNMOST TRACKS...SUCH AS THE ECMWF/UKMET/GFDL...SHOW A STRONGER RIDGE. OVERALL...MODELS HAVE SHIFTED A LITTLE TO THE SOUTH...AND I'M GOING TO CONTINUE TO LEAN THE FORECAST IN THAT DIRECTION. IF CURRENT TRENDS PERSIST...THE FORECAST COULD BE SHIFTED FARTHER TO THE SOUTH OR WEST LATER TONIGHT. IT SHOULD BE STRESSED THAT FOUR- AND FIVE-DAY TRACK FORECASTS CAN HAVE SIGNIFICANT ERRORS...AND ONE SHOULD NOT FOCUS ON THE EXACT TRACK. FORECAST POSITIONS AND MAX WINDS INITIAL 05/2100Z 22.9N 64.1W 100 KT 12HR VT 06/0600Z 22.6N 66.2W 95 KT 24HR VT 06/1800Z 22.2N 68.9W 95 KT 36HR VT 07/0600Z 22.1N 71.3W 100 KT 48HR VT 07/1800Z 22.2N 73.7W 110 KT 72HR VT 08/1800Z 23.0N 78.2W 115 KT 96HR VT 09/1800Z 24.5N 81.5W 115 KT 120HR VT 10/1800Z 25.5N 83.0W 115 KT $$ FORECASTER BLAKE/BEVEN |
