WTNT42 KNHC 300858
TCDAT2
HURRICANE GUSTAV DISCUSSION NUMBER 22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072008
500 AM EDT SAT AUG 30 2008
GUSTAV HAS BEEN RAPIDLY INTENSIFYING DURING THE OVERNIGHT HOURS. SATELLITE IMAGES INDICATE THAT AN EYE IS BECOMING VISIBLE AND DEEP CONVECTION SURROUNDING THE EYE IS NOW VERY INTENSE. THE CENTRAL PRESSURE IS DOWN TO 965 MB...A DROP OF ABOUT 24 MB IN 24 HOURS. THE MAXIMUM FLIGHT LEVEL WINDS REPORTED BY THE AIR FORCE CREW WERE 100 KT AROUND 6Z... CORRESPONDING TO ABOUT 90 KT AT THE SURFACE. HOWEVER THE SATELLITE PRESENTATION HAS CONTINUED TO IMPROVE...THUS THE INITIAL INTENSITY IS INCREASED CONSERVATIVELY TO 95 KT. OBJECTIVE DVORAK T-NUMBERS ARE MUCH HIGHER AND THE NEXT AIRCRAFT PASS THROUGH GUSTAV COULD FIND A MAJOR HURRICANE.
FURTHER INTENSIFICATION IS EXPECTED FOR THE NEXT DAY OR SO WHILE THE SYSTEM TRAVERSES THE EXTREMELY WARM AND DEEP WATERS OF THE NORTHWESTERN CARIBBEAN SEA AND SOUTHERN GULF OF MEXICO. HOWEVER...BY 48 HOURS...ALMOST ALL OF THE GLOBAL MODELS SHOW AN INCREASE IN VERTICAL WIND SHEAR NEAR GUSTAV. IN ADDITION...SINCE THE LOOP CURRENT IS SOUTH OF ITS TYPICAL LOCATION...THE HURRICANE WILL BE MOVING OVER WATERS THAT ARE NOT NEARLY AS CONDUCIVE FOR STRENGTHENING AS THEY COULD BE. THESE TWO FACTORS WILL HOPEFULLY WEAKEN THE STORM PRIOR TO U.S. LANDFALL. HOWEVER...GUSTAV IS EXPECTED TO BE A LARGE AND DANGEROUS HURRICANE AND THE NHC FORECAST CONTINUES TO SHOW GUSTAV AS A MAJOR HURRICANE AT LANDFALL.
THE INITIAL MOTION ESTIMATE IS 310/10. A MID-LEVEL RIDGE FROM THE WESTERN ATLANTIC TO NORTHERN FLORIDA IS EXPECTED TO CONTINUE MOVING THE HURRICANE TO THE NORTHWEST FOR THE NEXT COUPLE OF DAYS. THEREAFTER...A RIDGE OVER THE OHIO VALLEY SHOULD CAUSE A GRADUAL LEFTWARD BEND IN THE TRACK AS GUSTAV APPROACHES THE NORTHERN GULF COAST. MOST OF THE GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO EXCEPT FOR THE UKMET/HWRF...WHICH TURN THE SYSTEM JUST OFFSHORE. THESE TWO MODELS ARE SLOWER AND TO THE LEFT OF MOST OF THE TRACK GUIDANCE...WHICH ALLOWS A RIDGE TO FORM OVER TEXAS TO TURN THE STORM. THE OFFICIAL FORECAST WILL STAY WITH THE MAJORITY OF THE GUIDANCE AND IS BASICALLY AN UPDATE TO THE PREVIOUS PACKAGE. GUSTAV WILL LIKELY SLOW DOWN SIGNIFICANTLY IN THE LONGER-TERM...WHICH COULD CAUSE A CONSIDERABLE FLOODING THREAT OVER LOUISIANA OR TEXAS.
FORECAST POSITIONS AND MAX WINDS
INITIAL 30/0900Z 20.2N 81.3W 95 KT
12HR VT 30/1800Z 21.2N 82.7W 105 KT
24HR VT 31/0600Z 22.9N 84.6W 110 KT
36HR VT 31/1800Z 24.6N 86.4W 115 KT
48HR VT 01/0600Z 26.5N 88.3W 110 KT
72HR VT 02/0600Z 29.5N 91.5W 100 KT...NEAR LOUISIANA COAST
96HR VT 03/0600Z 30.5N 93.0W 70 KT...INLAND
120HR VT 04/0600Z 31.0N 94.0W 35 KT...INLAND
$$
FORECASTER BLAKE/AVILA
110 Knots is about 126 mph.