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HURRICANE BONNIE DISCUSSION NUMBER  19
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT MON AUG 24 1998
 
AIR FORCE RESERVE AIRCRAFT FIXES SHOW THAT THE MOTION IS STILL SLOW
AND ERRATIC.  THE PAST 12 HOUR MOTION IS 320/04 AND THIS WILL BE
USED AS THE INITIAL MOTION.
 
THE TRACK GUIDANCE IS FASCINATING.  THE GFDL MODEL HAS CHANGED
DRAMATICALLY FROM THE PREVIOUS RUN.  INSTEAD OF MOVING TO SOUTH
CAROLINA IN 72 HOURS...THE LATEST RUN...BASED ON EXCELLENT DATA FROM
A MULTI AIRCRAFT MISSION TO INITIALIZE THE 00Z ANALYSIS...SHOWS
THE NARROW RIDGE TO THE NORTH BREAKING DOWN AND BONNIE ACCELERATING
NORTH NORTHWESTWARD AND THEN RECURVING NORTHEASTWARD AND STAYING
OFFSHORE OF THE OUTER BANKS BY 100 MILES.  IN CONTRAST THE NOGAPS
AND UKMET MODELS CONTINUE TO SHOW A SLOW NORTHWEST MOTION TOWARD
GEORGIA OR SOUTH CAROLINA.  MY FORECAST TRACK IS A COMPROMISE WHICH
PUTS THE CENTER ON THE SOUTHERN COAST OF NORTH CAROLINA IN 72 HOURS.
THIS IS A STRATEGY OF LEAST REGRET...SO THAT INTERESTS ALONG THE
SOUTHEAST U.S. COAST CONTINUE TO PLAN FOR THE WORST...EVEN THOUGH
THE MOST LIKELY SCENARIO MAY BE THAT OF THE GFDL MODEL.
 
RECON GPS DROPSONDES SHOW THAT THE CENTRAL SUFACE PRESSURE HAS RISEN
SEVERAL MB SINCE YESTERDAY TO 963 MB.  THE HIGHEST SURFACE WIND
REPORTED USING GPS SONDS DURING THE LATEST MISSION WAS 94 KNOTS IN
THE NORTHWEST QUADRANT.  SINCE WE WERE PREVIOUSLY USING 100 KNOTS AS
THE MAX SURFACE WIND...THIS VALUE WILL BE RETAINED FOR THIS
ADVISORY.  THE SHIPS STATISTICAL/DYNAMICAL INTENSITY MODEL SHOWS
LITTLE CHANGE FOR 36 HOURS FOLLOWED BY SLIGHT WEAKENING.  THE
OFFICIAL FORECAST WILL BE FOR 100 KNOTS...NO CHANGE THROUGH 72 HOURS
SINCE SSTS ARE QUITE WARM.
 
LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     24/0900Z 25.2N  72.2W   100 KTS
12HR VT     24/1800Z 26.0N  73.0W   100 KTS
24HR VT     25/0600Z 27.2N  74.0W   100 KTS
36HR VT     25/1800Z 28.8N  75.2W   100 KTS
48HR VT     26/0600Z 30.5N  76.5W   100 KTS
72HR VT     27/0600Z 34.5N  78.0W   100 KTS
 
 
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