Skip Navigation Links weather.gov   
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
National Hurricane Center
Local forecast by
"City, St" or "ZIP"

 
Alternate Formats
   Text     |   Mobile
   Email   |   RSS XML/RSS logo
   About Alternates
Cyclone Forecasts
   Latest Advisory
   Past Advisories
   Audio/Podcasts
   About Advisories
Marine Forecasts
   Atlantic & E Pacific
   Gridded Marine
   About Marine
Tools & Data
   Satellite | Radar
   Analysis Tools
   Aircraft Recon
   GIS Datasets
   Data Archive
Development
   Experimental
   Research
   Forecast Accuracy
Outreach & Education
   Prepare
   Storm Surge
   About Cyclones
   Cyclone Names
   Wind Scale
   Most Extreme
   Forecast Models
   Breakpoints
   Resources
   Glossary | Acronyms
   Frequent Questions
Our Organization
   About NHC
   Mission & Vision
   Staff | Q&A
   Visitors | Virtual Tour
   Library Branch
   NCEP | Newsletter
Contact Us
   Comments
Follow the National Hurricane Center on Facebook Follow the National Hurricane Center on Twitter
Subscribe the National Hurricane Center on YouTube Read the National Hurricane Center Inside the Eye blog on WordPress
FirstGov.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.
 
 

Hurricane BILL


ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
HURRICANE BILL DISCUSSION NUMBER  21
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL032009
1100 AM AST THU AUG 20 2009
 
CONVENTIONAL SATELLITE...MICROWAVE IMAGES AND NUMEROUS OBSERVATIONS
FROM A NOAA P-3 RESEARCH PLANE INDICATE THAT BILL HAS WEAKENED A
LITTLE BIT DURING THE PAST SEVERAL HOURS.  DVORAK T-NUMBERS HAVE
DECREASED SINCE YESTERDAY...THE EYEWALL HAS BECOME OPEN TO THE
SOUTHWEST AND THE MAXIMUM FLIGHT LEVEL AND SFMR WINDS WERE 121 AND
93 KNOTS...RESPECTIVELY...EARLIER THIS MORNING. IN FACT...SOME ARC
CLOUDS ARE MOVING AWAY FROM THE HURRICANE SUGGESTING THAT BILL IS
NOT STRENGTHENING AT THIS TIME.  BASED ON THESE DATA...THE INITIAL
INTENSITY HAS BEEN REDUCED TO 105 KNOTS...AND THIS IS PROBABLY ON
THE HIGH SIDE.  THE LARGE SCALE ENVIRONMENT IS CONDUCIVE FOR
REINTENSIFICATION SINCE BILL IS ABOUT TO ENCOUNTER THE WARMEST
WATERS ALONG ITS PATH SO FAR...AND THE SHEAR IS FORECAST TO BE
QUITE LIGHT.  HOWEVER...MOST OF THE INTENSITY CHANGE COULD BE
ASSOCIATED WITH EYEWALL REPLACEMENT CYCLES. THE OFFICIAL FORECAST
CALLS FOR RESTRENGTHENING AND BILL IS EXPECTED TO REACH CATEGORY
FOUR AGAIN IN A DAY OR SO.  THEREAFTER...THE HURRICANE SHOULD
GRADUALLY BEGIN TO INTERACT WITH A MID-LATITUDE TROUGH AND BY 96
HOURS IT SHOULD BE IN EXTRATROPICAL TRANSITION AND BE FULLY
EXTRATROPICAL IN FIVE DAYS.
 
BILL HAS CONTINUED TO MOVE ON A STEADY NORTHWEST TRACK OR 305
DEGREES AT 16 KNOTS...EMBEDDED WITHIN THE FLOW SURROUNDING THE
AZORES-BERMUDA HIGH.  IN ABOUT TWO DAYS...THE HURRICANE WILL BECOME
STEERED NORTHWARD AND THEN NORTHEASTWARD BY THE FLOW BETWEEN A
LARGE MID-LATITUDE TROUGH SWINGING EASTWARD ACROSS THE EASTERN
UNITED STATES AND THE SUBTROPICAL HIGH. ONCE THE RECURVATURE
BEGINS...THE HURRICANE SHOULD INCREASE IN FORWARD SPEED. MOST OF
THE TRACK GUIDANCE SHIFTED SLIGHTLY TO THE WEST COMPARED TO THE
PREVIOUS RUN. THIS SHIFT IN GUIDANCE JUSTIFIES A VERY SMALL SHIFT
TO THE WEST OF THE TRACK OFFICIAL FORECAST...WHICH INDEED IS VERY
CLOSE TO THE CONSENSUS.
 
LARGE SWELLS GENERATED BY THIS HURRICANE ARE AFFECTING THE NORTHERN
LEEWARD ISLANDS AND SHOULD BEGIN AFFECTING THE BAHAMAS...BERMUDA...
MOST OF THE EASTERN U.S. COAST...AND THE ATLANTIC MARITIMES OF
CANADA 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 FOR
MORE DETAILS.
 
THIS AFTERNOON NOAA AND THE 53RD HURRICANE HUNTERS WILL BE
CONDUCTING A TWO-AIRCRAFT SYNOPTIC SURVEILLANCE MISSION AROUND
HURRICANE BILL TO IMPROVE THE INITIAL ANALYSIS FOR THE NUMERICAL
MODELS.

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      20/1500Z 22.6N  61.7W   105 KT
 12HR VT     21/0000Z 24.2N  63.8W   110 KT
 24HR VT     21/1200Z 26.6N  66.0W   115 KT
 36HR VT     22/0000Z 29.5N  67.5W   115 KT
 48HR VT     22/1200Z 32.5N  69.0W   110 KT
 72HR VT     23/1200Z 40.5N  66.5W   100 KT
 96HR VT     24/1200Z 48.0N  53.0W    65 KT...BECOMING EXTRATROPICAL
120HR VT     25/1200Z 55.0N  28.0W    50 KT...EXTRATROPICAL
 
$$
FORECASTER AVILA
 
NNNN


Quick Navigation Links:
Tropical Cyclone Forecasts  -  Tropical Marine Forecasts  -  Data Archive
Outreach  -  Prepare  -  About Cyclones  -  About NHC  -  Contact Us

NOAA/ National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Credits
Information Quality
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities
Page last modified: Thursday, 31-Dec-2009 12:09:05 UTC