000
WTNT43 KNHC 222034
TCDAT3
HURRICANE BILL DISCUSSION NUMBER  30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
500 PM AST SAT AUG 22 2009
 
AN AIR FORCE PLANE JUST PENETRATED AND SURVEYED HURRICANE BILL AND
ALTHOUGH IT MEASURED A MINIMUM CENTRAL PRESSURE OF 961 MB...THE
SURFACE WINDS REPORTED BY THE PLANE HAVE DECREASED...AND THE
INITIAL INTENSITY IS LOWERED TO 75 KNOTS. THIS INTENSITY IS ALSO
SUPPORTED BY T-NUMBERS WHICH HAVE BEEN BETWEEN 4.0 AND 5.0 ON THE
DVORAK SCALE. BILL IS EXPECTED TO MAINTAIN ITS STRENGTH FOR THE
NEXT SEVERAL HOURS BUT WITH COLD WATERS AHEAD...A GRADUAL WEAKENING
SHOULD BEGIN TONIGHT. BILL SHOULD BE FULLY EXTRATROPICAL IN ABOUT
48 HOURS AFTER THE CENTER PASSES NEAR OR OVER NEWFOUNDLAND.
 
THERE HAS BEEN NO SIGNIFICANT CHANGE IN TRACK. BILL IS MOVING
TOWARD THE NORTH OR 360 DEGREES AT ABOUT 21 KNOTS. THE HURRICANE IS
ALREADY EMBEDDED WITHIN THE FLOW BETWEEN THE AZORES-BERMUDA HIGH
AND A MID-LATITUDE TROUGH OVER THE EASTERN UNITED STATES. THIS
PATTERN SHOULD FORCE BILL TO TURN TO THE NORTH-NORTHEAST TONIGHT
WITH A GRADUAL INCREASE IN FORWARD SPEED. THE GUIDANCE CONTINUES
TO BE TIGHTLY PACKED...RESULTING IN HIGH CONFIDENCE IN THE TRACK
FORECAST. THE FORECAST TRACK BRINGS BILL TO THE WATERS JUST SOUTH
OF NOVA SCOTIA IN 24 HOURS AND VERY NEAR OR OVER NEWFOUNDLAND
BETWEEN 24 AND 36 HOURS AS A WEAKENING CYCLONE.
 
LARGE SWELLS GENERATED BY BILL ARE STILL AFFECTING THE EAST COAST OF
THE UNITED STATES. THESE SWELLS WILL CONTINUE TO SPREAD NORTHWARD
TONIGHT AND SUNDAY...CAUSING EXTREMELY DANGEROUS SURF AND
LIFE-THREATENING RIP CURRENTS. PLEASE CONSULT STATEMENTS ISSUED BY
YOUR LOCAL WEATHER OFFICE AND METEOROLOGICAL SERVICES FOR MORE
DETAILS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      22/2100Z 37.1N  68.8W    75 KT
 12HR VT     23/0600Z 40.2N  67.6W    75 KT
 24HR VT     23/1800Z 44.2N  63.2W    65 KT
 36HR VT     24/0600Z 48.0N  54.5W    45 KT...INLAND
 48HR VT     24/1800Z 50.0N  43.0W    40 KT...EXTRATROPICAL
 72HR VT     25/1800Z 52.0N  20.0W    30 KT...EXTRATROPICAL
 96HR VT     26/1800Z 57.0N   7.0W    25 KT...EXTRATROPICAL
120HR VT     27/1800Z 64.0N   2.5W    30 KT...EXTRATROPICAL
 
$$
FORECASTER AVILA