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HURRICANE BONNIE DISCUSSION NUMBER  23
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT TUE AUG 25 1998
 
LATEST RECON FIXES SHOW A MOTION OF 330/08 OVER THE PAST 12 HOURS
COMPARED TO 325/05 12 HOURS AGO...SO THE FORWARD MOTION APPEARS TO
BE INCREASING. THE PAST 6 HOUR MOTION IS 10 KNOTS.   USING THE
MULTI-AIRCRAFT MISSION DATA AND THE 00Z AVIATION RUN...THE GFDL
MODEL SHOWS ABOUT THE SAME TRACK AS BEFORE...PASSING ABOUT 75 N.MI.
EAST OF THE OUTER BANKS IN 36 HOURS AND THEN ACCELERATING TOWARD THE
NORTHEAST.  THE UKMET SHOWS A LANDFALL IN SOUTHERN N.C. IN ABOUT 60
HOURS AND THE NOGAPS SHOWS A LANDFALL NEAR CHARLESTON IN 48
HOURS.  THE OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY AND ABOUT HALFWAY BETWEEN THE UKMET AND GFDL AND PUTS THE
CENTER ACROSS THE OUTER BANKS IN 36 TO 48 HOURS.
 
THE 34 KNOT WIND RADII IS ABOUT 165 N.M. IN THE NORTHWEST QUADRANT
BASED ON A GPS DROPSONDE.  ON THE FORECAST TRACK...GALES WILL REACH
THE N.C. COAST IN ABOUT 24 TO 30 HOURS FROM 09Z...SO IT IS TIME TO
PUT UP A HURRICANE WARNING.
 
IF THE NOGAPS TURNS OUT TO BE CORRECT...THE MOVEMENT SHOULD BE
SLOWER AND THERE WILL BE MORE TIME BEFORE WARNINGS ARE NEEDED
FURTHER SOUTH.
 
THE LAST RECON CENTRAL SURFACE PRESSURE WAS 963 MB AND THE 117 KNOT
FLIGHT LEVEL WIND STILL STANDS AS THE HIGHEST WIND SPEED DURING THE
LAST RECON MISSION.  LATER PASSES FAILED TO FIND A WIND NEAR THAT
VALUE...BUT SINCE THE PRESSURE REMAINS THE SAME...THE WIND SPEED
WILL BE KEPT AT 100 KNOTS AND THE FORECAST WIND SPEED IS THE SAME AS
THE PREVIOUS ADVISORY.
 
LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     25/0900Z 28.1N  74.0W   100 KTS
12HR VT     25/1800Z 29.4N  74.9W   100 KTS
24HR VT     26/0600Z 31.6N  75.6W   100 KTS
36HR VT     26/1800Z 33.8N  76.0W   100 KTS
48HR VT     27/0600Z 36.5N  75.5W   100 KTS
72HR VT     28/0600Z 40.0N  70.0W    85 KTS
 
 
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