Tropical Storm GUILLERMO

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TROPICAL STORM GUILLERMO DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT SAT AUG 09 2003
 
AFTER LOSING MUCH OF ITS THUNDERSTORM ACTIVITY EARLIER THIS
AFTERNOON...A RECENT BURST OF DEEP CONVECTION HAS OCCURRED NEAR THE
LOW LEVEL CIRCULATION OF GUILLERMO. HOWEVER...SATELLITE INTENSITY
ESTIMATES REMAIN UNCHANGED WITH 55 KT FROM TAFB...45 KT FROM
SAB...AND 35 KT FROM AFWA.  THE INITIAL INTENSITY IS SET AT 45 KT
BASED ON A BLEND OF THE THREE ESTIMATES. 
 
SATELLITE IMAGERY INDICATES THAT GUILLERMO MAY BE TAKING A SMALL JOG 
MORE TO THE NORTH.  HOWEVER...THIS IS ASSUMED TO BE A SHORT-TERM
FLUCTUATION AND THE INITIAL MOTION ESTIMATE REMAINS ESSENTIALLY
UNCHANGED AT 270/12. THE TRACK FORECAST IS SHIFTED SLIGHTLY TO THE
NORTH DURING THE FIRST 48 HOURS WITH NO SIGNIFICANT CHANGES
THEREAFTER.
 
IN TERMS OF INTENSITY...GUILLERMO IS STUCK BETWEEN A ROCK AND A HARD
PLACE AND THE INTENSITY FORECAST IS A BIT LESS STRAIGHTFORWARD. A
MIDDLE TO UPPER LEVEL TROUGH LIES WEST OF GUILLERMO WHICH IS
RESTRICTING OUTFLOW AND PRODUCING SUBSIDENCE OVER THE WESTERN
SEMICIRCLE. TO THE EAST...DEVELOPING T.S. HILDA WITH ITS UPPER
LEVEL OUTFLOW EXPANDING WESTWARD. FOR NOW...THE UPPER TROUGH TO THE
WEST OF GUILLERMO APPEARS TO BE THE PRIMARY FACTOR FOR INTENSITY
CHANGE. IT IS PRODUCING A SEMI-FAVORABLE ENVIRONMENT AS EVIDENCED
BY THE RECENT BURST OF CONVECTION AND GOOD OUTFLOW TO THE NORTH. 
HOWEVER...WITH TIME THIS UPPER TROUGH SHOULD PRODUCE INCREASING
SHEAR OVER GUILLERMO AND SLOWLY WEAKEN THE SYSTEM.  THIS IS IN LINE
WITH THE INCREASING SHEAR FORECAST BY THE SHIPS MODEL. GUILLERMO IS
EXPECTED TO REMAIN OVER SUFFICIENTLY WARM SST...SO THAT SHOULD NOT
BE AN INHIBITING FACTOR. HOWEVER...IT IS UNCLEAR HOW MUCH INFLUENCE
THE DEVELOPING T.S. HILDA WILL HAVE ON GUILLERMO.
 
FORECASTER RHOME/AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/0300Z 15.4N 125.2W    45 KT
 12HR VT     10/1200Z 15.5N 126.9W    50 KT
 24HR VT     11/0000Z 15.6N 129.3W    45 KT
 36HR VT     11/1200Z 15.6N 131.7W    45 KT
 48HR VT     12/0000Z 15.6N 134.4W    45 KT
 72HR VT     13/0000Z 15.3N 140.0W    40 KT
 96HR VT     14/0000Z 15.0N 146.0W    35 KT
120HR VT     15/0000Z 15.0N 151.5W    35 KT
 
 
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