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HURRICANE DANIELLE DISCUSSION NUMBER  11
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT WED AUG 26 1998
 
AIR FORCE RECONNAISSANCE AIRCRAFT HAS FOUND A 70-KNOT DANIELLE WHICH
IS VERY ASYMMETRIC IN ITS WIND FIELD WITH MAXIMUM FLIGHT LEVEL WINDS
OF 37 KNOTS OVER THE SOUTHWEST QUAD...77 KNOTS OVER THE NORTHEAST
QUAD AND 73 KNOTS OVER THE NORTHEAST QUAD.  THE LARGE ASYMMETRY IS
UNDOUBTABLY DUE TO THE LARGE...18 KNOTS...TRANSLATION SPEED AND THE
LARGE PRESSURE GRADIENT ASSOCIATED WITH THE RIDGE TO THE NORTH. 
THEREFORE THE WIND RADII WILL CHANGE SUBSTANTIALLY WITH THIS
PACKAGE.  THE LOWEST ESTIMATED SURFACE PRESSURE WAS 992MB LOCATED
NEAR THE WIND MINIMUM.

SATELLITE IMAGES CONTINUE TO SHOW STRONG SOUTHERLY SHEAR DISRUPTING
THE CLOUD PATTERN ASSOCIATED WITH DANIELLE.  DVORAK INTENSITY
ESTIMATES REMAIN AT 4.5 OR ABOUT 75 KNOTS.
 
WE NOW ESTIMATE THE SURFACE WINDS TO BE 70 KNOTS AT THE SURFACE AND
HOLD THAT INTENSITY THROUGH 24 HOURS...INCREASING THE FORECAST
INTENSITY TO 95 KNOTS AT 72 HOURS.  THIS IS IN RESPONSE TO THE
REDUCTION IN FORECAST VERTICAL SHEAR FOR THE LATTER PERIODS.  THIS
IS IN KEEPING WITH THE SHIPS INTENSITY FORECAST.   
 
INITIAL MOTION IS 285/18.  A STRONG MID-TROPOSPHERIC HIGH CONTINUES
TO BE FORECAST TO BUILD OVER THE NORTH CENTRAL ATLANTIC.  IN
RESPONSE TO THAT FEATURE...THE GFDL..BAM-DEEP...NOGAPS AND LBAR
MODELS MAINTAIN THE SAME WEST-NORTHWEST TRACK THROUGH 48 HOURS AND
THEN MORE TO THE NORTHWEST.  THE OFFICIAL FORECAST GOES ALONG WITH
THESE MODELS THROUGH 48 HOURS AND THEN MORE WITH THE GFDL AND NOGAPS
AT 72 HOURS.  SOME DECREASE IN FORWARD SPEED IS ALSO FORECAST.
 
GROSS
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     27/0300Z 20.4N  55.7W    70 KTS
12HR VT     27/1200Z 21.1N  58.4W    70 KTS
24HR VT     28/0000Z 22.2N  61.4W    70 KTS
36HR VT     28/1200Z 23.1N  64.4W    75 KTS
48HR VT     29/0000Z 24.1N  67.6W    80 KTS
72HR VT     30/0000Z 26.6N  73.9W    95 KTS
 
 
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