WTPA44 PHFO 171445
TCDCP4

TROPICAL STORM GUILLERMO DISCUSSION NUMBER  22
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP102009
500 AM HST MON AUG 17 2009

TROPICAL STORM GUILLERMO CONTINUES TO WEAKEN. MOST OF THE COLDER
CLOUD TOPS HAVE NOW BEEN SHEARED OFF AND THE DEEP CONVECTION HAS
COMPLETELY DISSIPATED. THE LOW LEVEL CENTER IS NOW COMPLETELY
EXPOSED ON THE SOUTHWEST SIDE OF THE SYSTEM. GUILLERMO IS CLEARLY
CONTINUING TO WEAKEN RATHER QUICKLY DUE TO STRONG WEST-SOUTHWEST
SHEAR. RECENT MICROWAVE PASSES HAVE STILL SHOWN HEAVY RAIN WRAPPING
AROUND THE NORTH SIDE OF GUILLERMO SO THE SYSTEM STILL HAS SOME
PUNCH LEFT. I PUT THE INITIAL INTENSITY AT 50 KT...A BIT LOWER THAN
THE SUBJECTIVE DVORAK ANALYSES. THE DVORAK CONSTRAINTS MAY BE
MAKING THE INTENSITY ESTIMATES A BIT TOO HIGH IN THIS RAPIDLY
SHEARING SYSTEM.

NOW THAT THE LOW LEVEL CENTER IS COMPLETELY EXPOSED...WE HAVE HIGH
CONFIDENCE IN THE CENTER LOCATION. IT APPEARS THAT THE FORWARD
SPEED HAS INCREASED AND THAT GUILLERMO HAS STARTED TO CURVE TOWARD
THE NORTHWEST. I HAVE SHIFTED THE TRACK A BIT TO THE LEFT OF THE
PREVIOUS TRACK. AS GUILLERMO CONTINUES TO WEAKEN AND BECOME
SHALLOWER THE TRACK IS LIKELY TO BE MORE STRONGLY INFLUENCED BY THE
LOW LEVEL EASTERLY FLOW.
  
GUILLERMO REMAINS OVER COOL...24.5 DEGREES CELSIUS...WATER AND
STRONG...30 KT...WEST-NORTHWEST SHEAR. WITH SUCH AN UNFAVORABLE
ENVIRONMENT...GUILLERMO CAN BE EXPECTED TO CONTINUE WEAKENING
RATHER RAPIDLY. GUILLERMO WILL MOVE OVER WARMER WATER AFTER ABOUT
36 HOURS...BUT IT MAY NOT MATTER SINCE THE SHEAR WILL BECOME EVEN
STRONGER. ONCE GUILLERMO HAS BEEN REDUCED TO A SHALLOW LOW...WARMER
WATER IS UNLIKELY TO BE ENOUGH TO ALLOW THE SYSTEM TO REGENERATE.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/1500Z 21.5N 144.5W    50 KT
 12HR VT     18/0000Z 22.4N 146.9W    45 KT
 24HR VT     18/1200Z 23.7N 150.0W    40 KT
 36HR VT     19/0000Z 25.3N 153.0W    35 KT
 48HR VT     19/1200Z 26.7N 156.2W    30 KT
 72HR VT     20/1200Z 28.7N 162.8W    25 KT...DISSIPATING
 96HR VT     21/1200Z 29.1N 169.1W    20 KT...REMNANT LOW
120HR VT     22/1200Z 28.3N 174.8W    20 KT...REMNANT LOW
 
$$
FORECASTER DONALDSON