Blogging About Hurricane Bill #10

000
WTNT33 KNHC 211454
TCPAT3
BULLETIN
HURRICANE BILL ADVISORY NUMBER 25...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
1100 AM AST FRI AUG 21 2009

CORRECTED FOR TRACK PARAGRAPH

...LARGE HURRICANE BILL ON A STEADY NORTHWESTWARD TRACK...RAINBANDS
ALREADY AFFECTING BERMUDA...

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...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 1100 AM AST...1500 UTC...THE CENTER OF HURRICANE BILL WAS LOCATED
NEAR LATITUDE 27.6 NORTH...LONGITUDE 66.3 WEST OR ABOUT 335 MILES...
540 KM...SOUTH-SOUTHWEST OF BERMUDA AND ABOUT 755 MILES...1215 KM...
SOUTHEAST OF CAPE HATTERAS NORTH CAROLINA.

BILL IS MOVING TOWARD THE NORTHWEST NEAR 18 MPH...30 KM/HR. A
GRADUAL TURN TO THE NORTH-NORTHWEST AND THEN NORTH IS EXPECTED
LATER TODAY 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 115 MPH...185 KM/HR...WITH HIGHER
GUSTS. BILL IS A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON
SCALE. SOME FLUCTUATIONS IN INTENSITY ARE LIKELY TODAY AND
SATURDAY.

BILL REMAINS A LARGE TROPICAL CYCLONE. HURRICANE FORCE WINDS EXTEND
OUTWARD UP TO 115 MILES...185 KM...FROM THE CENTER...AND TROPICAL
STORM FORCE WINDS EXTEND OUTWARD UP TO 290 MILES...465 KM. RADAR
FROM BERMUDA INDICATES THAT SOME RAINBANDS ARE ALREADY AFFECTING
BERMUDA.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 958 MB...28.29 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 FORECAST 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 1100 AM AST INFORMATION...
LOCATION...27.6N 66.3W
MAXIMUM SUSTAINED WINDS...115 MPH
PRESENT MOVEMENT...NORTHWEST OR 325 DEGREES AT 18 MPH
MINIMUM CENTRAL PRESSURE...958 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 200 PM AST FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 500
PM AST.

$$
FORECASTER AVILA

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

000
WTNT43 KNHC 211448
TCDAT3
HURRICANE BILL DISCUSSION NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
1100 AM AST FRI AUG 21 2009

AFTER SOME DETERIORATION OF THE CLOUD PATTERN EARLY THIS
MORNING...VISIBLE SATELLITE IMAGES INDICATE THAT THE EYE HAS BECOME
APPARENT AGAIN ALTHOUGH IS NOT AS DISTINCT IT WAS YESTERDAY.
MICROWAVE IMAGES SHOW A CONVECTIVE RING ASSOCIATED WITH THE EYEWALL
WITH AN OUTER CONVECTIVE BAND. AT THIS POINT IT IS DIFFICULT TO
KNOW WHETHER THIS IS THE BEGINNING OF THE FORMATION OF A SECONDARY
EYEWALL. IT IS ALSO POSSIBLE THAT THE WEAKENING OVERNIGHT WAS
RELATED TO AN EYEWALL REPLACEMENT CYCLE. THE AVERAGE OF THE LATEST
OBJECTIVE AND SUBJECTIVE DVORAK T-NUMBERS INDICATE THAT INITIAL
INTENSITY CAN BE ADJUSTED DOWN TO 100 KT. AN AIR FORCE HURRICANE
HUNTER PLANE WILL CHECK THE INTENSITY LATER TODAY. THE HURRICANE
STILL HAS TO MOVE OVER THE WARMEST OCEAN YET TODAY AND
SATURDAY...AND THE SHEAR IS LOW AS DIAGNOSED BY THE SHIPS MODEL.
BILL HAS THE POTENTIAL TO RESTRENGTHEN A LITTLE BUT MOST LIKELY THE
HURRICANE WILL EXPERIENCE SOME FLUCTUATIONS IN INTENSITY DURING THE
NEXT 24 HOURS. THEREAFTER...SHEAR AND A COLDER OCEAN SHOULD WORK
AGAINST INTENSIFICATION AND BILL SHOULD BEGIN ITS EXTRATROPICAL
TRANSITION BEYOND 72 HOURS.

BILL IS MOVING TOWARD THE NORTHWEST OR 325 DEGREES AT 16 KNOTS WHILE
EMBEDDED IN VERY WELL-ESTABLISHED STEERING CURRENTS ASSOCIATED WITH
THE AZORES-BERMUDA HIGH. BILL IS ALREADY REACHING THE SOUTHWESTERN
EDGE OF THE RIDGE AND SOON WILL BECOME STEERED NORTHWARD AND
NORTHEASTWARD BY THE FLOW BETWEEN THE HIGH AND A LARGE MID-LATITUDE
TROUGH DEVELOPING OVER THE EASTERN UNITED STATES. THESE TWO
FEATURES ARE BEING HANDLED CONSISTENTLY ACROSS MOST OF THE
DYNAMICAL MODELS AND CONSEQUENTLY THE TRACK GUIDANCE IS TIGHTLY
PACKED. THE FACT THAT TRACK GUIDANCE IS IN VERY GOOD AGREEMENT
INCREASES MY 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.


FORECAST POSITIONS AND MAX WINDS

INITIAL 21/1500Z 27.6N 66.3W 100 KT
12HR VT 22/0000Z 29.8N 67.7W 100 KT
24HR VT 22/1200Z 33.0N 68.5W 100 KT
36HR VT 23/0000Z 36.5N 68.4W 90 KT
48HR VT 23/1200Z 41.0N 66.0W 80 KT
72HR VT 24/1200Z 48.5N 52.0W 60 KT
96HR VT 25/1200Z 53.5N 27.5W 50 KT...EXTRATROPICAL
120HR VT 26/1200Z 57.5N 10.0W 40 KT...EXTRATROPICAL

$$
FORECASTER AVILA