Hurricane HILARY

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HURRICANE HILARY DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT SUN AUG 21 2005

THE ORGANIZATION OF THE HURRICANE IS SLOWLY INCREASING...WITH A VERY
COLD CDO ON CONVENTIONAL IR IMAGES AND BANDING FEATURES EVIDENT ON
MICROWAVE IMAGERY.  INTENSITY ESTIMATES...USING THE EMBEDDED CENTER
PATTERN WITH THE DVORAK TECHNIQUE...WERE 77 AND 65 KT FROM SAB AND
TAFB RESPECTIVELY.  CURRENT INTENSITY IS SET AT 70 KT.  HILARY HAS
STRONG UPPER-LEVEL OUTFLOW TO THE SOUTH AND WEST...WHICH IS
INDICATIVE OF SOME NORTHEASTERLY SHEAR.  GLOBAL MODEL UPPER-LEVEL
WIND FORECASTS INDICATE THAT THIS SHEAR WILL DIMINISH OVER THE NEXT
COUPLE OF DAYS.  SOME OF THE PARAMETERS SHOWN TO BE IMPORTANT IN
THE STATISTICAL SCHEME FOR FORECASTING SIGNIFICANT
INTENSIFICATION...SUCH AS AN ABUNDANCE OF COLD CLOUD TOPS AND HIGH
RELATIVE HUMIDITY IN THE LOW- TO MID-TROPOSPHERE... ARE PRESENT. 
CURIOUSLY... HOWEVER...THE LATEST SHIPS MODEL RUN HAS BACKED OFF A
LITTLE ON ITS INTENSITY FORECAST.  THE OFFICIAL WIND SPEED FORECAST
FOR THIS ADVISORY IS SIMILAR TO THE PREVIOUS ONE.

MICROWAVE FIXES FROM SSM/I...AMSU...AND WINDSAT...HAVE BEEN HELPFUL
IN LOCATING THE CENTER.  USING THESE FIXES...THE INITIAL MOTION
ESTIMATE...280/11...IS A LITTLE SLOWER THAN BEFORE.  A MID-LEVEL
RIDGE TO THE NORTH OF THE HURRICANE IS FORECAST TO WEAKEN IN ABOUT
48 HOURS IN RESPONSE TO A TROUGH THAT DROPS INTO CALIFORNIA.  IN
RESPONSE TO THESE CHANGES IN THE STEERING CURRENT...HILARY IS
FORECAST TO TURN TOWARD THE NORTHWEST AND SLOW LATER IN THE
FORECAST PERIOD.  HOWEVER...THE LATEST DYNAMICAL MODEL CONSENSUS
HAS SHIFTED A LITTLE TO THE LEFT AT 4-5 DAYS IN COMPARISON TO THE
PREVIOUS PACKAGE.  THE OFFICIAL TRACK FORECAST IS A LITTLE SLOWER
THAN IN THE PREVIOUS ADVISORY AND IS QUITE CLOSE TO THE FSU
SUPERENSEMBLE TRACK. 

RAINBANDS PRODUCING OCCASIONAL GUSTY WINDS AND LOCALLY HEAVY
RAINFALL ARE AFFECTING PORTIONS OF THE SOUTHWESTERN COAST OF MEXICO
WEST OF ACAPULCO.  CONDITIONS THERE SHOULD GRADUALLY IMPROVE AS
HILARY MOVES AWAY FROM THE COAST DURING THE NEXT DAY OR SO.
 
FORECASTER PASCH
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/0900Z 14.6N 105.3W    70 KT
 12HR VT     21/1800Z 15.2N 107.4W    80 KT
 24HR VT     22/0600Z 15.9N 109.9W    85 KT
 36HR VT     22/1800Z 16.7N 112.3W    90 KT
 48HR VT     23/0600Z 17.5N 114.3W    90 KT
 72HR VT     24/0600Z 19.0N 117.0W    80 KT
 96HR VT     25/0600Z 20.5N 118.5W    70 KT
120HR VT     26/0600Z 22.0N 120.0W    55 KT
 
 
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