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Hurricane HILARY


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HURRICANE HILARY DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 PM PDT SUN AUG 21 2005
 
VISIBLE IMAGERY AND ADDITIONAL MICROWAVE PASSES CONFIRMED THAT
HILARY INDEED HAD MOVED MORE TO THE NORTH THAN PREVIOUSLY
EXPECTED...ALONG A RAPID CYCLONICALLY CURVED ARC THAT ALREADY
APPEARS TO BE BENDING BACK TO THE LEFT AND SLOWING.  THE OVERALL
MOTION OVER THE PAST 18 HOURS IS 295/13.  HILARY IS EXPECTED TO
MOVE SOUTH OF THE SUBTROPICAL RIDGE OVER THE NEXT 36 HOURS OR
SO...WHEN A SIGNIFICANT EROSION OF THE RIDGE IS EXPECTED AS A
MID-LEVEL TROUGH BECOMES ESTABLISHED OVER SOUTHERN CALIFORNIA. 
THERE IS SOME SPREAD AMONG THE TRACK GUIDANCE MODELS AS TO HOW
HILARY WILL RESPOND TO THIS TROUGH...WITH THE UKMET AND NOGAPS
TURNING HILARY NORTHWESTWARD INTO THE WEAKNESS.  IN CONTRAST...THE
GFDL AND GFS SHOW LITTLE INTERACTION BETWEEN HILARY AND THE
TROUGH...AND INDEED TURN THE CYCLONE BACK TO THE WEST AFTER 96
HOURS.  ALL GUIDANCE AGREES ON A SLOWING OF THE FORWARD SPEED IN
ABOUT 36 HOURS.  SAVE FOR A NORTHWARD ADJUSTMENT DUE TO THE INITIAL
POSITION...THE OFFICIAL FORECAST IS VERY SIMILAR TO THE PREVIOUS
ADVISORY AND IS SLIGHTLY ON THE UKMET/NOGAPS SIDE OF THE DYNAMICAL
MODEL CONSENSUS.

THE CIRCULATION CENTER IS UNDERNEATH A SMALL BALL OF -80C
CONVECTION...WITH WELL DEFINED BANDS NEAR THE CORE IN THE SOUTHEAST
QUADRANT AND ADDITIONAL BANDS FARTHER OUT BOTH TO THE NORTH AND
SOUTH.  DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE NOT
CLOSE...90 AND 65 KT...RESPECTIVELY.  THE LATEST OBJECTIVE
INTENSITY ESTIMATE FROM CIMSS IS ABOUT 80 KT...T4.7...WHILE 
AMSU-BASED MICROWAVE ESTIMATES ARE BELOW HURRICANE STRENGTH.  GIVEN
ALL THE ABOVE...IT SEEMS APPROPRIATE TO RAISE THE ADVISORY
INTENSITY A LITTLE...TO 75 KT.  ONLY MODEST EASTERLY SHEAR IS
APPARENT IN VISIBLE AND WATER VAPOR IMAGERY...AND HILARY SHOULD
HAVE AT LEAST 36 HOURS OVER WARM WATER.  THEREFORE...ADDITIONAL
INTENSIFICATION IS EXPECTED AND THE OFFICIAL FORECAST IS CLOSE TO
THE SHIPS GUIDANCE THROUGH 48 HOURS.  AFTER THAT...SHIPS APPEARS TO
DECAY THE CYCLONE TOO SLOWLY OVER THE COLD WATER...WHERE THE
OFFICIAL FORECAST IS IN BETTER AGREEMENT WITH THE GFDL.
 
RAINBANDS PRODUCING OCCASIONAL GUSTY WINDS AND LOCALLY HEAVY
RAINFALL ARE AFFECTING PORTIONS OF THE SOUTHWESTERN COAST OF MEXICO
NEAR MANZANILLO.  CONDITIONS THERE SHOULD GRADUALLY IMPROVE AS
HILARY MOVES AWAY FROM THE COAST DURING THE NEXT DAY OR SO.
 
FORECASTER FRANKLIN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/2100Z 16.6N 107.8W    75 KT
 12HR VT     22/0600Z 17.4N 109.4W    85 KT
 24HR VT     22/1800Z 18.4N 111.9W    90 KT
 36HR VT     23/0600Z 19.3N 114.2W    90 KT
 48HR VT     23/1800Z 20.0N 115.5W    85 KT
 72HR VT     24/1800Z 21.0N 117.5W    70 KT
 96HR VT     25/1800Z 22.0N 119.5W    50 KT
120HR VT     26/1800Z 23.5N 122.0W    30 KT
 
 
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