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TROPICAL STORM ALLISON DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT TUE JUN 05 2001
 
REPORTS THIS AFTERNOON FROM AN AIR FORCE RESERVE RECONNAISSANCE 
AIRCRAFT INDICATE THE BROAD CIRCULATION OF ALLISON HAS MOVED LITTLE. 
ALSO...SATELLITE AND SURFACE OBSERVATIONS INDICATE SEVERAL SMALLER 
VORTICES HAVE MOVED OUT FROM UNDER THE DEEP CONVECTION TOWARD THE 
TEXAS COAST SOUTH OF GALVESTON...WHICH HAS COMPLICATED THE LOCATION 
ESTIMATE PROCESS.  THE ADVISORY POSITION HAS BEEN ADJUSTED WEST OF 
THE PREVIOUS LOCATION...BUT JUST EAST OF THE RECON POSITIONS BASED 
ON SYNOPTIC ANALYSES OF THE BROADER LOW-LEVEL CIRCULATION.
 
INITIAL MOTION ESTIMATE IS 360/10.  THERE IS NO SIGNIFICANT CHANGE 
TO PREVIOUS TRACK PHILOSOPHY OTHER THAN TO SHIFT THE TRACK A LITTLE 
TO THE LEFT BASED ON THE WESTWARD REPOSITIONING OF THE BROAD 
LOW-LEVEL CIRCULATION CENTER.  TROPICAL STORM ALLISON IS EXPECTED TO 
CONTINUE MOVING NORTHWARD AROUND THE WESTERN PERIPHERY OF THE 
SUBTROPICAL RIDGE...WHICH IS FORECAST TO REMAIN ORIENTED EAST-WEST 
ACROSS THE SOUTHERN U.S. FROM GEORGIA TO LOUISIANA THROUGH THE 
FORECAST PERIOD. THE BROAD CENTER SHOULD MOVE INLAND OVER EXTREME 
SOUTHEAST TEXAS OR SOUTHWEST LOUISIANA LATER TONIGHT AND THEN TURN 
MORE TOWARD THE NORTHEAST AS A SHORTWAVE TROUGH OVER THE SOUTHERN 
PLAINS GRADUALLY PICKS UP THE SYSTEM.  THIS SCENARIO IS CONSISTENT 
WITH MOST OF THE GLOBAL MODELS.
 
SOME SLIGHT STRENGTHENING IS POSSIBLE BEFORE LANDFALL EVEN THOUGH
ALLISON IS A HYBRID SYSTEM.  HOWEVER...IT IS UNLIKELY THAT THE 
CYCLONE WOULD GET ABOVE 55 KT DUE TO THE COOL OFFSHORE SEA SURFACE 
TEMPERATURES.  THE INTENSITY WAS HELD UP SLIGHTLY AT 12 HOURS EVEN 
THOUGH THE SYSTEM CENTER IS EXPECTED TO BE INLAND.  THIS IS DUE TO 
THE LONG FETCH OF SOUTHEASTERLY TROPICAL STORM FORCE WINDS TO STILL 
BE SPREADING ONSHORE THE LOUISIANA COAST AT THAT TIME.
 
FORECASTER STEWART
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     05/2100Z 28.8N  95.1W    50 KTS
12HR VT     06/0600Z 30.4N  95.1W    45 KTS...INLAND
24HR VT     06/1800Z 32.2N  94.8W    30 KTS...INLAND DISSIPATING
36HR VT     07/0600Z 33.6N  93.9W    25 KTS...INLAND DISSIPATING
48HR VT     07/1800Z 34.5N  92.6W    20 KTS...INLAND DISSIPATING

 
 
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