Hurricane GUILLERMO

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HURRICANE GUILLERMO DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP102009
800 PM PDT FRI AUG 14 2009
 
VISIBLE AND INFRARED SATELLITE IMAGERY REVEALS AN IMPRESSIVE CLOUD
PATTERN ASSOCIATED WITH GUILLERMO...WITH MANY OF THE STRUCTURAL
CHARACTERISTICS OF A MATURE HURRICANE.  THE CYCLONE HAS MAINTAINED
A RAGGED...BANDING-TYPE EYE SINCE EARLIER TODAY...THOUGH IT HAS
RECENTLY BECOME CLOUD-FILLED. ADDITIONALLY...TWO WELL-ORGANIZED
BANDS ARE COILING AROUND A CENTRAL DENSE OVERCAST. EVEN THOUGH
DVORAK T-NUMBERS HAVE DECREASED TO 4.5 FROM BOTH TAFB AND SAB AT 00
UTC...THE CONVECTIVE ORGANIZATION OF GUILLERMO HAS IMPROVED IN THE
LAST HOUR OR TWO. BASED UPON ITS MOST RECENT SATELLITE
APPEARANCE...THE INTENSITY IS HELD AT 85 KT THIS ADVISORY. 
 
THE INITIAL MOTION ESTIMATE REMAINS 285/14...ESSENTIALLY NO
DIFFERENT THAN BEFORE.  GUILLERMO IS MOVING AROUND THE SOUTHWEST
SIDE OF A DEEP-LAYER ANTICYCLONE EXTENDING FROM THE SOUTH CENTRAL
UNITED STATES INTO THE SUBTROPICAL EAST PACIFIC PAST 140W.  THERE
HAS BEEN NO CHANGE TO THE TRACK PHILOSOPHY...WITH THIS FEATURE
FORECAST TO KEEP GUILLERMO ON A TRACK JUST NORTH OF DUE WEST
THROUGH 72 HOURS. THEREAFTER...THE CYCLONE SHOULD BE APPROACHING A
WEAKNESS IN THE VICINITY OF THE HAWAIIAN ISLANDS WHICH SHOULD
INDUCE A MORE WEST-NORTHWESTWARD COURSE.  THE MODEL CONSENSUS HAS
EDGED SLIGHTLY NORTH BEYOND 72 HOURS...POSSIBLY IN RESPONSE TO THE
AFORMENTIONED WEAKNESS.
 
LAST VISIBLE PICTURES SHOW GUILLERMO PUSHING INTO A DENSE FIELD OF
STRATOCUMULUS...INDICATIVE OF PROGRESSIVELY COOLER SEA SURFACE
TEMPERATURES AHEAD OF IT.  THIS IS THE MAIN FACTOR WHICH SHOULD
LEAD TO GRADUAL WEAKENING DURING THE NEXT 24-36 HOURS...EVEN WHILE
THE ENVIRONMENTAL SHEAR REMAINS RELATIVELY LOW.  THEREAFTER...
INCREASING SOUTHWESTERLY SHEAR ASSOCIATED WITH A RETROGRADING MID-
TO UPPER-LEVEL TROUGH AROUND 150-160W SHOULD ACCELERATE THE
WEAKENING TREND. GUILLERMO IS FORECAST TO BECOME A REMNANT LOW BY
THE END OF THE FORECAST PERIOD AND COULD WEAKEN FASTER THAN
FORECAST IF THE SHEAR IS AS HIGH AS SHIP MODEL GUIDANCE SUGGESTS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      15/0300Z 18.3N 130.3W    85 KT
 12HR VT     15/1200Z 18.7N 132.3W    80 KT
 24HR VT     16/0000Z 19.3N 135.0W    70 KT
 36HR VT     16/1200Z 19.9N 137.6W    60 KT
 48HR VT     17/0000Z 20.5N 140.2W    50 KT
 72HR VT     18/0000Z 22.2N 145.3W    40 KT
 96HR VT     19/0000Z 24.0N 150.5W    30 KT
120HR VT     20/0000Z 26.0N 156.0W    25 KT...REMNANT LOW
 
$$
FORECASTER KIMBERLAIN
 
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