Hurricane HILARY

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HURRICANE HILARY DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 PM PDT MON AUG 22 2005
 
THE WEAKENING TREND NOTED ON THE LAST ADVISORY CONTINUES WITH THE
CENTRAL CORE OF THE HURRICANE STILL LACKING SIGNIFICANT DEEP
CONVECTION. AN AVERAGE OF THE DVORAK AND CURRENT INTENSITY NUMBERS
FROM TAFB AND SAB WARRANTS BRINGING DOWN THE INITIAL INTENSITY
SLIGHTLY TO 80 KT. ALTHOUGH THE SHIPS GUIDANCE INDICATES THAT THE
SHEAR IS EXPECTED TO REMAIN WEAK THROUGHOUT THE
FORECAST...WEAKENING IS ANTICIPATED DUE TO AN INCREASINGLY STABLE
ENVIRONMENT AND A TRACK ACROSS COOLER WATERS. WATER VAPOR IMAGERY
INDICATES A LARGE AREA OF DRY AIR TO THE WEST OF HILARY AND THE
STORM MAY BEGIN ENTRAINING SOME OF THIS AIR OVER THE NEXT 24 HOURS.
THE FORECAST CALLS FOR A SLOW WEAKENING IN THE FIRST 24 HOURS WITH
STEADIER WEAKENING BEYOND THAT TIME AS HILARY IS EXPECTED TO CROSS
OVER WATERS COOLER THAN 26C. THE OFFICIAL WIND SPEED FORECAST IS
CLOSER TO THE SHIPS GUIDANCE WHICH IS NOT AS AGGRESSIVE IN
WEAKENING THE CYCLONE AS THE GFDL. HILARY IS EXPECTED TO BEGIN
DISSIPATING IN 96 HOURS AND BECOME A REMNANT LOW BY THE END OF THE
FORECAST PERIOD.
 
THE FORWARD SPEED OF HILARY HAS SLOWED AND IS SLIGHTLY TO THE RIGHT
OF THE PREVIOUS PACKAGE...295/9. THIS IS IN RESPONSE TO A WEAKENING
OF THE MID-LEVEL RIDGE TO THE NORTH OF THE HURRICANE. A SLIGHT
DECREASE IN FORWARD SPEED IS FORECAST OVER THE NEXT 48 HOURS. AFTER
THAT TIME...THE MID LEVEL RIDGE IS EXPECTED TO BUILD WESTWARD AND A
MUCH WEAKER HILARY SHOULD BE STEERED MORE TO THE WEST. THE OFFICIAL
FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS PACKAGE GIVEN THE
SAME GENERAL REASONING. 
 
BOTH THE 34 KT WIND AND 12 FT SEAS RADII WERE ADJUSTED IN THE SE
QUADRANT BASED ON A SHIP REPORT FROM SHIP WITH CALL SIGN
MHCO7.
 
FORECASTER COBB/KNABB
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      23/0300Z 19.1N 113.6W    80 KT
 12HR VT     23/1200Z 19.6N 115.0W    75 KT
 24HR VT     24/0000Z 20.2N 116.6W    70 KT
 36HR VT     24/1200Z 20.8N 118.0W    60 KT
 48HR VT     25/0000Z 21.5N 119.2W    50 KT
 72HR VT     26/0000Z 22.5N 122.5W    35 KT
 96HR VT     27/0000Z 23.0N 126.5W    25 KT...DISSIPATING
120HR VT     28/0000Z 23.5N 131.0W    20 KT...REMNANT LOW
  
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