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TROPICAL STORM BONNIE DISCUSSION NUMBER   6
NATIONAL WEATHER SERVICE MIAMI FL
10 PM EST THU AUG 20 1998
 
THE LAST FIX FROM THE HURRICANE HUNTERS AT 2327Z STILL HAD THE
CENTER ON THE SOUTH SIDE OF THE DEEPEST CONVECTION.  THE MINIMUM
CENTRAL PRESSURE HAS DROPPED TO 1001 MB...BUT THE MAX FLIGHT-LEVEL
WINDS HAVE NOT CHANGED MUCH FROM THIS AFTERNOON.  INITIAL INTENSITY
REMAINS AT 45 KNOTS.  ALTHOUGH THE OUTFLOW LOOKS IMPRESSIVE OVER THE
WESTERN SEMICIRCLE...BONNIE IS STILL EXPERIENCING SOME EASTERLY OR
SOUTHEASTERLY SHEAR.  THIS SHEAR IS EXPECTED TO DECREASE AND
ADDITIONAL STRENGTHENING IS FORECAST. 

INITIAL MOTION ESTIMATE IS 290/21.  MOST OF THE DYNAMICAL GUIDANCE
INDICATES A BREAKDOWN IN THE RIDGE TO THE NORTH OF BONNIE...
RESULTING IN A MORE NORTHWARD TURN OF THE TROPICAL CYCLONE AFTER 36
TO 48 HOURS.  THE OUTLIER TONIGHT IS STILL THE GFDL MODEL...WHICH
CONTINUES A MORE WESTWARD OR WEST-NORTHWESTWARD MOTION.  OUR
OFFICIAL TRACK IS ON THE LEFT SIDE OF NEARLY ALL OF THE GUIDANCE
BASED ON TREMENDOUS RESPECT FOR THE GFDL DEVELOPED OVER THE PAST FEW
YEARS.  OUR OFFICIAL TRACK IS WELL LEFT OF THE UKMET...NAVY
NOGAPS...AND AVIATION MODELS....BUT CONSIDERABLY TO THE RIGHT OF THE
GFDL.  

THE STEERING ENVIRONMENT IS CURRENTLY BEING SAMPLED BY A MAJOR
SYNOPTIC FLOW EXPERIMENT INVOLVING BOTH THE NOAA P-3S AND G-4
AIRCRAFT.  FIFTY-NINE GLOBAL POSITIONING SONDES WILL BE DEPLOYED
FROM THESE PLATFORMS FOR THE 00Z INITIALIZATION OF THE LARGE-SCALE
MODELS.
 
MAYFIELD
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     21/0300Z 19.0N  62.3W    45 KTS
12HR VT     21/1200Z 20.1N  65.4W    50 KTS
24HR VT     22/0000Z 21.7N  68.8W    55 KTS
36HR VT     22/1200Z 23.4N  71.2W    60 KTS
48HR VT     23/0000Z 25.1N  72.7W    70 KTS
72HR VT     24/0000Z 28.5N  73.5W    80 KTS
 
 
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