Blogging About Hurricane Bill #12

000
WTNT33 KNHC 212039
TCPAT3
BULLETIN
HURRICANE BILL ADVISORY NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST FRI AUG 21 2009

...HURRICANE BILL A LITTLE WEAKER...COULD REGAIN SOME STRENGTH ON
SATURDAY...

A TROPICAL STORM WARNING AND A HURRICANE WATCH ARE IN EFFECT FOR
BERMUDA.

INTERESTS 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...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 29.4 NORTH...LONGITUDE 66.9 WEST OR ABOUT 235 MILES...
380 KM...SOUTH-SOUTHWEST OF BERMUDA AND ABOUT 640 MILES...1035 KM...
SOUTHEAST OF CAPE HATTERAS NORTH CAROLINA.

BILL IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 20 MPH...32 KM/HR. A
GRADUAL TURN TOWARD THE NORTH IS EXPECTED TONIGHT AND SATURDAY. ON
THE FORECAST TRACK...THE CORE OF HURRICANE BILL IS EXPECTED TO PASS
OVER THE OPEN WATERS BETWEEN BERMUDA AND THE EAST COAST OF THE
UNITED STATES ON SATURDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR HAVE DECREASED TO NEAR 105
MPH...165 KM/HR...WITH HIGHER GUSTS. BILL IS A CATEGORY TWO
HURRICANE ON THE SAFFIR-SIMPSON SCALE. SOME STRENGTHENING IS STILL
POSSIBLE TONIGHT OR SATURDAY.

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 954 MB...28.17 INCHES.

BILL IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 1 TO 3
INCHES OVER BERMUDA...WITH MAXIMUM AMOUNTS OF 5 INCHES.

THE BERMUDA WEATHER SERVICE HAS INDICATED THAT THE STORM TIDE WILL
RAISE WATER LEVELS BY AS MUCH AS 3 FEET ABOVE GROUND LEVEL ALONG
THE COAST...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...IN
ADVANCE OF BILL.

LARGE SWELLS GENERATED BY THIS HURRICANE ARE AFFECTING PUERTO
RICO...HISPANIOLA...THE BAHAMAS...AND BERMUDA...AND SHOULD BEGIN
AFFECTING MOST OF THE U.S. EAST COAST AND THE ATLANTIC MARITIMES OF
CANADA DURING THE NEXT DAY OR TWO. THESE SWELLS WILL LIKELY CAUSE
EXTREMELY DANGEROUS SURF AND LIFE-THREATENING RIP CURRENTS.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...29.4N 66.9W
MAXIMUM SUSTAINED WINDS...105 MPH
PRESENT MOVEMENT...NORTH-NORTHWEST OR 340 DEGREES AT 20 MPH
MINIMUM CENTRAL PRESSURE...954 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

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

000
WTNT43 KNHC 212040
TCDAT3
HURRICANE BILL DISCUSSION NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST FRI AUG 21 2009

AN AIR FORCE HURRICANE HUNTER AIRCRAFT REACHED BILL THIS
AFTERNOON AND FOUND THAT THE CENTRAL PRESSURE HAS REMAINED AROUND
954 MB...BUT THE WINDS HAVE DECREASED AND INITIAL INTENSITY IS NOW
90 KT. THE PLANE REPORTED A SMALL EYE OF 14 N MI DIAMETER.
GIVEN THE CONCENTRIC RING STRUCTURE OBSERVED ON MICROWAVE AND THE
DOUBLE WIND MAXIMA PROVIDED BY THE PLANE...IT IS LIKELY THAT THE
HURRICANE IS GOING THROUGH AN EYEWALL REPLACEMENT AND THE REASON
FOR THE CURRENT WEAKENING. THERE IS AN OPPORTUNITY FOR BILL TO
REGAIN SOME STRENGTH DURING THE NEXT 12 TO 24 HOURS WHILE THE SHEAR
IS LOW AND BEFORE THE HURRICANE REACHES COOLER WATERS.
THEREAFTER...A STEADY WEAKENING IS INDICATED AND BY 72 HOURS...BILL
SHOULD ALREADY BE AN EXTRATROPICAL CYCLONE INTERACTING WITH THE
HIGH LATITUDE WESTERLIES.

BILL IS NOW MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 17
KNOTS. THE HURRICANE SHOULD GRADUALLY TURN MORE TO THE NORTH AROUND
THE BERMUDA-AZORES HIGH TONIGHT AND SATURDAY AND SHOULD BE FORCED TO
RECURVE AS A LARGE MID-LATITUDE TROUGH MOVES EASTWARD ACROSS THE
EASTERN UNITED STATES. THERE HAS NOT BEEN ANY CHANGE IN TRACK
GUIDANCE WHICH IN FACT CONTINUES TO BE TIGHTLY PACKED...MAINTAINING
HIGH CONFIDENCE IN THE TRACK FORECAST.

LARGE SWELLS GENERATED BY THIS HURRICANE WILL AFFECT A LARGE PORTION
OF THE WESTERN NORTH ATLANTIC COASTAL AREA 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 AND METEOROLOGICAL SERVICES FOR MORE
DETAILS.

AT THIS TIME...TROPICAL-STORM-FORCE WINDS ARE NOT FORECAST TO REACH
NEW ENGLAND. HOWEVER...A SLIGHT SHIFT OF THE FORECAST TRACK TO THE
LEFT WOULD REQUIRE A TROPICAL STORM WATCH OR WARNING TONIGHT. THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS ROUGHLY A 25
PERCENT CHANCE OF THESE WINDS REACHING EXTREME SOUTHEASTERN NEW
ENGLAND.

FORECAST POSITIONS AND MAX WINDS

INITIAL 21/2100Z 29.4N 66.9W 90 KT
12HR VT 22/0600Z 31.7N 68.0W 100 KT
24HR VT 22/1800Z 35.1N 68.4W 100 KT
36HR VT 23/0600Z 39.0N 67.2W 85 KT
48HR VT 23/1800Z 43.0N 64.0W 75 KT
72HR VT 24/1800Z 49.5N 47.0W 50 KT...EXTRATROPICAL
96HR VT 25/1800Z 54.5N 20.0W 45 KT...EXTRATROPICAL
120HR VT 26/1800Z 60.0N 6.0W 35 KT...EXTRATROPICAL

$$
FORECASTER AVILA