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HURRICANE BONNIE DISCUSSION NUMBER  20
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT MON AUG 24 1998

LATEST RECON FIX SHOWS LITTLE MOVEMENT...AGAIN.  WE STILL EXPECT A
NORTHWESTWARD MOTION TO RESUME BUT THE STEERING CURRENTS ARE STILL
VERY WEAK IN THE AREA.  LAST NIGHT...THE 00Z GFDL MODEL RUN MADE A
DRASTIC CHANGE...SHIFTING THE FORECAST TRACK TO THE EAST...AND THE
06Z RUN OF THIS MODEL TELLS ABOUT THE SAME STORY.  THE 06Z AVN RUN
OF THE NCEP GLOBAL SPECTRAL MODEL SHOWS THAT THE MID-TROPOSPHERIC
RIDGE HAS ENOUGH OF A BREAK IN THE VICINITY OF EASTERN NORTH
CAROLINA TO ALLOW BONNIE TO SLIP THROUGH AND INDEED MANY OF THE
TRACK GUIDANCE MODELS NOW SHOW RECURVATURE AWAY FROM THE COAST. 
HOWEVER THE 00Z NAVY NOGAPS MODEL REFUSES TO RECURVE BONNY...AND
BRINGS THE CYCLONE CLOSE TO THE GEORGIA/FLORIDA BORDER BY THE END OF
THE FORECAST PERIOD.  INTERESTINGLY...IT APPEARS THAT ABOUT 80 PER
CENT OF THE DROPWINDSONDES FROM YESTERDAYS MAJOR ENVIRONMENTAL
SAMPLING MISSION ENTERED INTO THAT MODEL SO IT CANNOT BE
DISREGARDED.  ANOTHER COMPLICATING FACTOR IS A MID- TO UPPER-LEVEL
TROUGH THAT WATER VAPOR IMAGERY SHOWS DROPPING INTO THE NORTH-
CENTRAL GULF OF MEXICO.  THIS FEATURE COULD EXERT SOME INFLUENCE ON
THE FUTURE TRACK OF BONNIE AS WELL.

INTENSITY ESTIMATE REMAINS NEAR 100 KNOTS.  EVEN THOUGH THE EYE HAS
DISAPPEARED...THE HURRICANE HUNTERS REPORTED 109 KNOT WINDS NEAR THE
700 MB LEVEL.  IF BONNIE MOVES A BIT MORE...IT WOULD LIKELY
ENCOUNTER WARMER WATERS AND THIS COULD ALLOW STRENGTHENING.  HOWEVER
THERE IS SOME SUGGESTION OF SOUTHWESTERLY SHEAR....PARTICULARLY IN
THE AVN MODEL OUTPUT...SO THIS COULD NEGATE STRENGTHENING.  THE
OFFICIAL FORECAST HOLDS THE WINDS AT 100 KNOTS THROUGH THE PERIOD.

NOTE...THE NHC INTERNET SITE IS DOWN AT THIS TIME.  SOME OF ITS
HURRICANE INFORMATION CAN BE OBTAINED FROM THE FEDERAL EMERGENCY
MANAGEMENT AGENCY AT 

WWW.FEMA.GOV/HLT/TROP.HTML

PASCH 

FORECAST POSITIONS AND MAX WINDS
 
INITIAL     24/1500Z 25.6N  72.4W   100 KTS
12HR VT     25/0000Z 26.4N  73.1W   100 KTS
24HR VT     25/1200Z 28.0N  74.1W   100 KTS
36HR VT     26/0000Z 29.7N  74.8W   100 KTS
48HR VT     26/1200Z 31.5N  75.5W   100 KTS
72HR VT     27/1200Z 35.5N  76.5W   100 KTS
 
 
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