Tropical Storm GUILLERMO

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TROPICAL STORM GUILLERMO DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT FRI AUG 08 2003

DVORAK INTENSITY ESTIMATES ARE UNCHANGED...SO MAXIMUM WINDS ARE HELD
AT 40 KT.  THE CLOUD PATTERN HAS BECOME CONSOLIDATED AND IS FAIRLY
WELL ORGANIZED...ALTHOUGH LACKING IN BANDING FEATURES.  VERTICAL
SHEAR APPEARS TO BE LIGHT OVER THE AREA...ALTHOUGH THE OUTFLOW
PATTERN SUGGESTS SLIGHT EASTERLY SHEAR.  SINCE THE STORM IS
FORECAST TO MOVE GENERALLY WESTWARD...WATER TEMPERATURES SHOULD
REMAIN JUST WARM ENOUGH TO ALLOW FURTHER STRENGTHENING.  WITH THE
ESTIMATED INTENSITY UNCHANGED OVER THE PAST 6 HOURS...THE SHIPS
MODEL SHOWS LESS STRENGTHENING THAN BEFORE...DUE TO A REDUCED
PERSISTENCE COMPONENT.  THE OFFICIAL INTENSITY FORECAST IS
ESSENTIALLY UNCHANGED FROM THE PREVIOUS ADVISORY.

LATEST CENTER FIXES SUGGEST A WESTWARD MOTION...AROUND 270/6.
THE GFS...U.K. MET OFFICE...AND NOGAPS MODELS ALL SHOW DEVELOPMENT
OF A DISTURBANCE LOCATED ABOUT 800 MILES TO THE EAST-SOUTHEAST OF
GUILLERMO.  IN THE GFS RUN...THE EASTERN SYSTEM QUICKLY BECOMES
DOMINANT SO THAT THE MODEL VORTEX TRACKER HAS DIFFICULTY FOLLOWING
THE CURRENT TROPICAL STORM.  THE NOGAPS AND U.K. MET OFFICE RUNS
KEEP GUILLERMO DISTINCT AND STRONGER.  IN ANY EVENT...THE STEERING
SCENARIO APPEARS TO BE RELATIVELY STRAIGHTFORWARD...ASSUMING THAT
GUILLERMO WILL HAVE MINIMAL INTERACTION WITH THE EASTERN
DISTURBANCE.   A MID-LEVEL RIDGE IS EXPECTED TO BE NORTH OF
GUILLERMO OVER THE NEXT FEW DAYS.  THEREFORE A CONTINUED WESTWARD
MOTION IS FORECAST...WITH A LITTLE INCREASE IN FORWARD SPEED.  THIS
IS A LITTLE SOUTH OF...AND SLIGHTLY FASTER THAN...THE PREVIOUS NHC
FORECAST TRACK.  THE GFDL AND NOGAPS ARE FASTER AND TO SOUTH OF THE
CURRENT NHC FORECAST.  

FORECASTER PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/0900Z 16.6N 118.2W    40 KT
 12HR VT     08/1800Z 16.7N 119.3W    45 KT
 24HR VT     09/0600Z 16.8N 121.3W    50 KT
 36HR VT     09/1800Z 16.9N 123.4W    55 KT
 48HR VT     10/0600Z 17.0N 125.5W    55 KT
 72HR VT     11/0600Z 17.0N 129.5W    50 KT
 96HR VT     12/0600Z 17.0N 133.0W    50 KT
120HR VT     13/0600Z 17.0N 136.5W    45 KT
 
 
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