000
WTPZ45 KNHC 161436
TCDEP5
HURRICANE GUILLERMO DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP102009
800 AM PDT SUN AUG 16 2009
 
SATELLITE IMAGES INDICATE THAT THE CLOUD CANOPY ASSOCIATED WITH
GUILLERMO IS BECOMING SOMEWHAT ASYMMETRIC AS THE CYCLONE BEGINS TO
FEEL THE EFFECTS OF INCREASING SHEAR.  HOWEVER...THE EYE REMAINS
DISTINCT AND RECENTLY THE EYEWALL CONVECTION HAS INCREASED A BIT. 
THE INITIAL INTENSITY IS HELD AT 85 KT.  A RAPID WEAKENING IS
LIKELY FOR GUILLERMO BY TONIGHT DUE TO A SIGNIFICANT INCREASE IN
VERTICAL WIND SHEAR AND ITS CONTINUED PASSAGE OVER COOL WATERS. THE
INTENSITY FORECAST IS SIMILAR TO THE LAST ONE AND IS IN GOOD
AGREEMENT WITH THE SHIPS MODEL.  GUILLERMO SHOULD TRANSITION TO A
REMNANT LOW IN A FEW DAYS DUE TO VERY STRONG VERTICAL WIND SHEAR.
 
THE INITIAL MOTION REMAINS 280/13.  THERE IS LITTLE CHANGE TO THE
SYNOPTIC REASONING WITH A MID-LEVEL RIDGE TO THE NORTHEAST OF
GUILLERMO STEERING THE HURRICANE ON A WEST-NORTHWEST PATH FOR THE
NEXT SEVERAL DAYS.  A LARGE MID- TO UPPER-LEVEL LOW DEVELOPING NEAR
HAWAII WILL LIKELY CAUSE A NORTHWESTWARD BEND IN THE TRACK BY THE
END OF THE FORECAST PERIOD.  THE TRACK FORECAST IS BASICALLY AN
UPDATE OF THE PREVIOUS PACKAGE WITH VERY FEW CHANGES IN MODEL
GUIDANCE NOTED.  
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      16/1500Z 20.1N 138.7W    85 KT
 12HR VT     17/0000Z 20.6N 140.7W    70 KT
 24HR VT     17/1200Z 21.6N 143.5W    55 KT
 36HR VT     18/0000Z 22.7N 146.4W    45 KT
 48HR VT     18/1200Z 24.0N 149.3W    40 KT
 72HR VT     19/1200Z 27.0N 155.0W    30 KT...REMNANT LOW
 96HR VT     20/1200Z 31.0N 162.0W    25 KT...REMNANT LOW
120HR VT     21/1200Z...DISSIPATED
 
$$
FORECASTER BLAKE