Tropical Storm GUILLERMO

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TROPICAL DEPRESSION GUILLERMO DISCUSSION NUMBER  19
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT MON AUG 11 2003
 
A FEW BURSTS OF CONVECTION DEVELOPED OVER THE CENTER BETWEEN 21-23Z
...BUT SINCE THEN THE CENTRAL CONVECTION HAS WEAKENED. HOWEVER...THE 
INITIAL INTENSITY IS BEING MAINTAINED AT 30 KT BASED ON THE PRESENCE
OF TWO INTERLOCKING BANDS OF MODERATE CONVECTION LOCATED NORTH AND
SOUTH OF THE CENTER. DVORAK SATELLITE CURRENT INTENSITY ESTIMATES
ARE ALSO 30 KT...OR T2.0...FROM TAFB AND AFWA.

THE INITIAL MOTION ESTIMATE REMAINS 275/13.  GUILLERMO IS EMBEDDED
IN MODERATE LOW-LEVEL EASTERLY STEERING FLOW ON THE SOUTH SIDE OF A
STRONG SUBTROPICAL RIDGE AND THIS PATTERN IS EXPECTED TO PERSIST
THROUGHOUT THE FORECAST PERIOD. THE OFFICIAL FORECAST TRACK IS A
LITTLE SOUTH OF THE PREVIOUS TRACK AND IS CLOSE TO A BLEND OF THE
GFS...GFS ENSEMBLE...GFDL...NOGAPS...AND UKMET MODELS...AND BRINGS
THE REMNANT LOW-LEVEL CIRCULATION TO WITHIN ABOUT 60 NMI SOUTH OF
THE BIG ISLAND OF HAWAII BY 120 HOURS.
 
WHILE THE NEW FORECAST TRACK KEEPS GUILLERMO OVER 26C SSTS A LITTLE
LONGER THAN PREVIOUSLY FORECAST...GRADUAL WEAKENING IS STILL
EXPECTED DUE TO INCREASING WESTERLY UPPER-LEVEL SHEAR OF 20-25 KT
THROUGHOUT THE FORECAST PERIOD. IN ADDITION...THE WARM SOUTHERLY
INFLOW APPEARS TO BE CUT OFF NOW BY THE INTERTROPICAL CONVERGENCE
ZONE THAT HAS REDEVELOPED SOUTH OF THE CYCLONE ALONG 12-13N
LATITUDE. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THE
PREVIOUS FORECAST AND IS MUCH LOWER THAN THE SHIPS INTENSITY
MODEL...WHICH BRINGS GUILLERMO BACK UP TO 51 KT IN 120 HOURS.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0300Z 16.4N 135.5W    30 KT
 12HR VT     12/1200Z 16.5N 137.2W    25 KT
 24HR VT     13/0000Z 16.7N 139.5W    25 KT...DISSIPATING
 36HR VT     13/1200Z 16.9N 141.8W    20 KT...REMNANT LOW
 48HR VT     14/0000Z 17.1N 144.0W    20 KT...REMNANT LOW
 72HR VT     15/0000Z 17.5N 148.5W    20 KT...REMNANT LOW
 96HR VT     16/0000Z 17.5N 152.5W    20 KT...REMNANT LOW
120HR VT     17/0000Z 18.0N 156.5W    20 KT...REMNANT LOW
 
 
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