Blogging About Hurricane Bill #17

000
WTNT33 KNHC 222114
TCPAT3
BULLETIN
HURRICANE BILL ADVISORY NUMBER 30...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST SAT AUG 22 2009

CORRECTED TO CHANGE PORT LAWRENCE TO FORT LAWRENCE IN TROPICAL STORM
WATCH AREA

...BILL EXPECTED TO TURN TOWARD THE NORTH-NORTHEAST EARLY SUNDAY...

AT 500 PM AST...2100 UTC...ENVIRONMENT CANADA HAS EXTENDED THE
TROPICAL STORM WARNING FROM ECUM SECUM TO POINT ACONI AND HAS
EXTENDED THE TROPICAL STORM WATCH FOR NEWFOUNDLAND FROM ARNOLDS COVE
NORTHWARD TO HARBOUR DEEP. A TROPICAL STORM WARNING MEANS THAT
TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING
AREA WITHIN 24 HOURS.

A TROPICAL STORM WARNING IS NOW IN EFFECT FROM CHARLESVILLE TO POINT
ACONI. A HURRICANE WATCH REMAINS IN EFFECT FROM ECUM SECUM TO POINT
ACONI.

A TROPICAL STORM WATCH REMAINS IN EFFECT FROM NORTH OF POINT ACONI
WESTWARD TO TIDNISH AND FROM VICTORIA IN QUEEN COUNTY NORTHWARD TO
LOWER DARNLEY IN PRINCE COUNTY...PRINCE EDWARD ISLAND...AND FOR THE
WESTERN PORTION OF NOVA SCOTIA FROM FORT LAWRENCE TO CHARLESVILLE.
A TROPICAL STORM WATCH IS ALSO IN EFFECT FROM PARSONS POND AROUND
THE SOUTHWESTERN PORTION OF NEWFOUNDLAND TO HARBOUR DEEP.

A TROPICAL STORM WARNING IS IN EFFECT FOR THE COAST OF MASSACHUSETTS
FROM WOODS HOLE TO SAGAMORE BEACH...INCLUDING THE ISLANDS OF
MARTHAS VINEYARD AND NANTUCKET.

INTERESTS ELSEWHERE ALONG THE COAST OF NEW ENGLAND AND IN THE
CANADIAN MARITIMES SHOULD MONITOR THE PROGRESS OF BILL.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE
MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE
FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA
OUTSIDE OF THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR NATIONAL METEOROLOGICAL SERVICE.

AT 500 PM AST...2100 UTC...THE CENTER OF HURRICANE BILL WAS LOCATED
NEAR LATITUDE 37.1 NORTH...LONGITUDE 68.8 WEST OR ABOUT 300 MILES...
480 KM...SOUTH-SOUTHEAST OF NANTUCKET MASSACHUSETTS AND ABOUT 585
MILES...940 KM...SOUTH-SOUTHWEST OF HALIFAX NOVA SCOTIA.

BILL IS MOVING TOWARD THE NORTH NEAR 24 MPH...39 KM/HR. THIS
MOTION IS EXPECTED TO CONTINUE TONIGHT WITH A GRADUAL TURN TO THE
NORTH-NORTHEAST ON SUNDAY. ON THE FORECAST TRACK...THE CORE OF
HURRICANE BILL SHOULD PASS OFFSHORE THE COAST OF NEW ENGLAND LATE
TODAY OR TONIGHT AND MOVE OVER OR NEAR NOVA SCOTIA ON SUNDAY.

MAXIMUM SUSTAINED WINDS HAVE DECREASED TO NEAR 85 MPH...140
KM/HR...WITH HIGHER GUSTS. BILL IS A CATEGORY ONE HURRICANE ON THE
SAFFIR-SIMPSON SCALE. WEAKENING IS EXPECTED TO BEGIN ON SUNDAY AS
BILL MOVES OVER COOLER WATERS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 85 MILES...140 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 275
MILES...445 KM.

THE MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE RECONNAISSANCE
AIRCRAFT WAS 961 MB...28.38 INCHES.

TOTAL RAIN ACCUMULATIONS OF 3 TO 5 INCHES WITH ISOLATED MAXIMUM
AMOUNTS OF 7 INCHES ARE EXPECTED NEAR THE TRACK OF BILL ACROSS NOVA
SCOTIA...PRINCE EDWARD ISLAND AND NEWFOUNDLAND. 1 TO 2 INCHES OF
RAIN ARE EXPECTED OVER NANTUCKET ISLAND...AND NEAR 1 INCH OVER OUTER
CAPE COD AND MARTHAS VINEYARD.

LARGE SWELLS GENERATED BY HURRICANE BILL ARE STILL AFFECTING THE
BAHAMAS AND BERMUDA BUT SHOULD GRADUALLY DIMINISH. THE LARGE SWELLS
SHOULD CONTINUE TO AFFECT MUCH OF THE U.S. EAST COAST AND THE
ATLANTIC MARITIMES OF CANADA TODAY AND SUNDAY. THESE SWELLS WILL
LIKELY CAUSE EXTREMELY DANGEROUS SURF AND LIFE-THREATENING RIP
CURRENTS.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...37.1N 68.8W
MAXIMUM SUSTAINED WINDS...85 MPH
PRESENT MOVEMENT...NORTH OR 360 DEGREES AT 24 MPH
MINIMUM CENTRAL PRESSURE...961 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 800 PM AST FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 1100
PM AST.

$$
FORECASTER AVILA/BRENNAN

-------------------------------------------------------------------------------------

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