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HURRICANE BONNIE DISCUSSION NUMBER  15
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT SUN AUG 23 1998

THE LAST AIR FORCE RESERVE RECONNAISSANCE REPORTED A MINIMUM CENTRAL
PRESSURE OF 959 MB...A 3 MB DECREASE SINCE 03Z AND AN 18 MB FALL IN
THE LAST 10 HOURS...AND A 25 NMI CIRCULAR EYE.  THE FLIGHT-LEVEL
WINDS HAVE NOW INCREASED WITH A MAXIMUM WIND OF 102 KNOTS RECORDED
IN THE NORTHEAST QUADRANT.  THE INITIAL INTENSITY WILL BE HELD AT 
90 KNOTS.  THE SATELLITE PRESENTATION REMAINS IMPRESSIVE WITH A
SYMMETRIC RING OF -75C TOPS SURROUNDING THE EYE AND EXCELLENT
OUTFLOW.  THE INTENSITY FORECAST CALLS FOR FURTHER STRENGTHENING
ALONG THE LINES OF THE PREVIOUS ADVISORY.

RECONNAISSANCE POSITION FIXES OVER THE LAST SEVERAL HOURS INDICATE
THAT THE MOTION OF BONNIE HAS BEEN SLOW AND ERRATIC.  THE INITIAL
MOTION ESTIMATE BASED ON THE LAST 6 HOURS IS 310/06 KNOTS.  AS HAS
BEEN THE CASE IN THE LAST SEVERAL ADVISORIES...THE FUTURE TRACK OF
BONNIE IS HINGED ON THE BREAKDOWN OF THE RIDGE NORTH OF THE SYSTEM. 
THE SYSTEM SHOULD TURN MORE TO THE NORTH-NORTHWEST AND NORTH DURING
THE NEXT 24 TO 48 HOURS...STEERED...IN PART...AROUND THE WESTERN
PERIPHERY OF A MID-LEVEL ANTICYCLONE TO THE EAST.  A TROUGH
CURRENTLY OVER THE NORTH CENTRAL U.S. IS FORECAST TO MOVE INTO THE
NORTHEAST U.S. IN THE NEXT 36 TO 48 HOURS WHICH MAY HELP TURN BONNIE
MORE NORTHWARD.  THE AVIATION SHOWS THIS TROUGH MOVING FAR ENOUGH
SOUTH TO PULL BONNIE NORTH WHILE THE NAVY NOGAPS MODEL INDICATES
THAT THE TROUGH STAYS SUFFICIENTLY NORTH TO ALLOW A MORE NORTHWEST
MOTION.  

THE OFFICIAL FORECAST TRACK IS VERY SIMILAR TO THE PREVIOUS ADVISORY
AND IS IN CLOSEST AGREEMENT WITH THE GFDL...AND SLIGHTLY LEFT OF THE
UKMET.   NOGAPS MODEL IS THE LEFT-MOST OF THE GUIDANCE.   ALTHOUGH
THIS TRACK LESSENS THE THREAT OF LANDFALL IN FLORIDA...INTERESTS IN
FLORIDA SHOULD CONTINUE TO CLOSELY MONITOR THE PROGRESS OF BONNIE
UNTIL THE EXPECTED TURN MATERIALIZES.  HISTORICALLY...THE LARGEST
TRACK ERRORS OCCUR WITH RE-CURVING SYSTEMS.
 
GUINEY
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     23/0900Z 23.8N  71.7W    90 KTS
12HR VT     23/1800Z 24.3N  72.3W    95 KTS
24HR VT     24/0600Z 25.3N  73.2W   100 KTS
36HR VT     24/1800Z 26.6N  74.2W   105 KTS
48HR VT     25/0600Z 28.5N  75.0W   110 KTS
72HR VT     26/0600Z 33.0N  76.0W   110 KTS
 
 
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