[Tropical] Tropical Cyclone Discussion

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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
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