Blogging About Hurricane Bill #2

000
WTNT33 KNHC 182103
TCPAT3
BULLETIN
HURRICANE BILL ADVISORY NUMBER 14...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST TUE AUG 18 2009

CORRECTED TO CHANGE WORD HUNGER TO HUNTER

...BILL APPROACHING MAJOR HURRICANE STATUS...

INTERESTS IN THE LEEWARD ISLANDS SHOULD MONITOR THE PROGRESS OF
BILL.

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
BY AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT NEAR LATITUDE 16.6
NORTH...LONGITUDE 52.2 WEST OR ABOUT 635 MILES...1025 KM...EAST OF
THE LEEWARD ISLANDS.

BILL IS MOVING TOWARD THE WEST-NORTHWEST NEAR 16 MPH...26 KM/HR. A
WEST-NORTHWEST MOTION IS EXPECTED TO CONTINUE TONIGHT...FOLLOWED BY
A TURN TOWARD THE NORTHWEST ON WEDNESDAY. ON THIS TRACK...THE CORE
OF BILL WILL BE PASSING WELL TO THE NORTHEAST OF THE NORTHERN
LEEWARD ISLANDS LATE WEDNESDAY AND EARLY THURSDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 110 MPH...175 KM/HR...WITH HIGHER
GUSTS. BILL IS A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON
SCALE. STRENGTHENING IS FORECAST DURING THE NEXT DAY OR TWO AND
BILL IS EXPECTED TO BECOME A MAJOR HURRICANE TONIGHT OR WEDNESDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175
MILES...280 KM.

THE MINIMUM CENTRAL PRESSURE REPORTED BY RECONNAISSANCE AIRCRAFT WAS
962 MB...28.41 INCHES.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...16.6N 52.2W
MAXIMUM SUSTAINED WINDS...110 MPH
PRESENT MOVEMENT...WEST-NORTHWEST OR 290 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...962 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 PM AST.

$$
FORECASTER BROWN/CANGIALOSI

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

000
WTNT43 KNHC 182047
TCDAT3
HURRICANE BILL DISCUSSION NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST TUE AUG 18 2009

BILL REMAINS A VERY IMPRESSIVE AND SYMMETRIC HURRICANE IN SATELLITE
IMAGERY. THE AIR FORCE HURRICANE HUNTER AIRCRAFT INVESTIGATING
BILL THIS AFTERNOON REPORTED PEAK 700 MB FLIGHT-LEVEL WINDS OF 114
KT IN THE NORTHEAST QUADRANT. THE SFMR OBSERVED MAXIMUM WINDS
AROUND 85 KT IN EACH QUADRANT OF THE HURRICANE. USING A BLEND OF
THESE DATA...THE INITIAL INTENSITY HAS BEEN INCREASED TO 95 KT.
THIS IS ALSO SUPPORTED BY SUBJECTIVE DVORAK INTENSITY ESTIMATES OF
90 AND 102 KT FROM SAB AND TAFB RESPECTIVELY.

THE INITIAL MOTION IS 290/14. THE FORECAST SCENARIO REMAINS
UNCHANGED FROM THE PREVIOUS ADVISORY. BILL IS EXPECTED TO
GRADUALLY TURN TO THE NORTHWEST DURING THE NEXT DAY OR TWO AS A
WEAKNESS DEVELOPS IN THE SUBTROPICAL RIDGE OVER THE WESTERN
ATLANTIC. THEREAFTER...THE HURRICANE IS FORECAST TO TURN NORTHWARD
AHEAD OF A STRONG TROUGH MOVING INTO THE EASTERN UNITED STATES.
THE TRACK GUIDANCE ENVELOPE CHANGED VERY LITTLE THROUGH 48
HOURS...BUT HAS GENERALLY SHIFTED WESTWARD DURING THE REMAINDER OF
THE FORECAST PERIOD. AS BEFORE THE ECMWF AND GFS ARE ON THE RIGHT
SIDE OF THE ENVELOPE WHILE THE UKMET IS ON THE LEFT. THE OFFICIAL
FORECAST IS VIRTUALLY UNCHANGED THROUGH DAY 2...AND HAS NOT BEEN
ADJUSTED APPRECIABLY BEYOND THAT TIME AS WELL. THE NEW FORECAST
LIES BETWEEN THE DYNAMICAL MODEL CONSENSUS AND THE USUALLY
WELL-PERFORMING ECMWF AND GFS MODELS.

VERTICAL WIND SHEAR IS EXPECTED TO REMAIN LOW AND SSTS GRADUALLY
INCREASE ALONG THE FORECAST TRACK DURING THE NEXT COUPLE OF DAYS.
THE INTENSITY FORECAST CALLS FOR ADDITIONAL STRENGTHENING DURING THE
NEXT COUPLE OF DAYS IN LINE WITH THE CONSENSUS OF THE INTENSITY
GUIDANCE. BEYOND 72 HOURS...DECREASING SSTS AND INCREASING
SOUTHWESTERLY UPPER-LEVEL WINDS AHEAD OF THE AFOREMENTIONED TROUGH
SHOULD INDUCE SLOW WEAKENING.

FORECAST POSITIONS AND MAX WINDS

INITIAL 18/2100Z 16.6N 52.2W 95 KT
12HR VT 19/0600Z 17.5N 54.3W 105 KT
24HR VT 19/1800Z 18.9N 56.9W 115 KT
36HR VT 20/0600Z 20.7N 59.3W 115 KT
48HR VT 20/1800Z 22.6N 61.8W 115 KT
72HR VT 21/1800Z 27.3N 65.8W 110 KT
96HR VT 22/1800Z 33.5N 68.0W 100 KT
120HR VT 23/1800Z 40.5N 65.5W 85 KT

$$
FORECASTER BROWN/CANGIALOSI