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Hurricane BILL (Text)

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HURRICANE BILL DISCUSSION NUMBER  22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
500 PM AST THU AUG 20 2009
 
BOTH NOAA AND AIR FORCE RECONNAISSANCE PLANES HAVE BEEN SENDING VERY
VALUABLE DATA FROM HURRICANE BILL. THE LATEST MINIMUM PRESSURE WAS
DOWN TO 948 MB AND THE PEAK FLIGHT-LEVEL WIND WAS 135 KNOTS. THE
SFMR REPORTED EARLIER A PEAK WIND OF 101 KNOTS.  SINCE THEN...THE
SATELLITE PRESENTATION HAS IMPROVED AND THE EYE IS NOW BETTER
DEFINED. IN FACT...GOES SATELLITE SUPER-RAPID SCAN SHOWS THE
STRUCTURE OF THE EYEWALL AND SEVERAL MESOVORTICES INSIDE THE
EYE...TYPICAL OF STRONG HURRICANES. BASED ON THE AIRCRAFT DATA AND
THE CURRENT SATELLITE PRESENTATION...THE INITIAL INTENSITY IS
ADJUSTED UPWARD TO 110 KNOTS.  THE LARGE SCALE ENVIRONMENT
CONTINUES TO BE CONDUCIVE FOR REINTENSIFICATION SINCE BILL IS ABOUT
TO ENCOUNTER THE WARMEST WATERS ALONG ITS PATH SO FAR.
FURTHERMORE...GLOBAL MODELS SHOW BILL EMBEDDED IN A WELL DEFINED
200 MB ANTICYCLONE. GIVEN THE FAVORABLE ENVIRONMENT...THE OFFICIAL
FORECAST CALLS FOR RESTRENGTHENING AND BILL IS EXPECTED TO REACH
CATEGORY FOUR STATUS AGAIN WITHIN THE NEXT 12 TO 36 HOURS.
THEREAFTER...THE HURRICANE SHOULD GRADUALLY BEGIN TO INTERACT WITH
A MID-LATITUDE TROUGH AND BY 96 HOURS IT SHOULD BE EXTRATROPICAL.
 
THERE IS PRACTICALLY NO CHANGE IN THE FORECAST TRACK. BILL IS MOVING
TOWARD THE NORTHWEST OR 305 DEGREES AT 16 KNOTS EMBEDDED IN VERY
STRONG AND WELL DEFINED STEERING CURRENTS AROUND THE SOUTHWESTERN
PORTION OF THE AZORES-BERMUDA HIGH. HOWEVER...IN A DAY OR SO A
LARGE MID-LATITUDE TROUGH IS EXPECTED TO SWEEP ACROSS THE EASTERN
UNITED STATES AND THE FLOW BETWEEN THE TROUGH AND THE SUBTROPICAL
HIGH SHOULD FORCE THE HURRICANE TO MOVE ON A NORTHERLY AND THEN
NORTHEASTERLY TRACK.  THE DYNAMICAL TRACK GUIDANCE IS EXTREMELY
TIGHTLY CLUSTERED DURING THE FIRST 48 HOURS...INCREASING
CONSIDERABLY THE CONFIDENCE IN THE OFFICIAL TRACK FORECAST FOR THAT
PERIOD.  ON THIS TRACK...THE CORE OF THE HURRICANE WILL MOVE OVER
THE OPEN WATERS BETWEEN BERMUDA AND THE EAST COAST OF THE UNITED
STATES SATURDAY MORNING AND BY SUNDAY...THE HURRICANE WILL BE
APPROACHING THE WATERS SOUTH OF NOVA SCOTIA. 
 
LARGE SWELLS GENERATED BY THIS HURRICANE ARE AFFECTING THE NORTHERN
LEEWARD ISLANDS...PUERTO RICO...HISPANIOLA AND SHOULD BEGIN
AFFECTING THE BAHAMAS...BERMUDA...MOST OF THE EASTERN U.S.
COAST...AND THE ATLANTIC MARITIMES OF CANADA DURING THE NEXT FEW
DAYS.  THESE SWELLS WILL LIKELY CAUSE EXTREMELY DANGEROUS SURF AND
LIFE-THREATENING RIP CURRENTS. PLEASE CONSULT STATEMENTS ISSUED BY
YOUR LOCAL WEATHER OFFICE FOR MORE DETAILS.
 
THE NOAA AND THE 53RD AIR FORCE RESERVE HURRICANE HUNTERS ARE
CURRENTLY CONDUCTING A TWO-AIRCRAFT SYNOPTIC SURVEILLANCE MISSION
AROUND HURRICANE BILL TO IMPROVE THE INITIAL ANALYSIS FOR THE
NUMERICAL MODELS. THIS INFORMATION WILL BE INCLUDED FOR THE 0000
UTC MODEL RUN.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/2100Z 23.8N  63.2W   110 KT
 12HR VT     21/0600Z 25.6N  65.2W   115 KT
 24HR VT     21/1800Z 28.3N  67.1W   115 KT
 36HR VT     22/0600Z 31.0N  68.5W   115 KT
 48HR VT     22/1800Z 34.5N  69.0W   105 KT
 72HR VT     23/1800Z 42.5N  64.5W    85 KT
 96HR VT     24/1800Z 49.0N  49.5W    60 KT...EXTRATROPICAL
120HR VT     25/1800Z 53.5N  24.0W    50 KT...EXTRATROPICAL
 
$$
FORECASTER AVILA/BLAKE
 
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