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HURRICANE DANIELLE DISCUSSION NUMBER  19
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT FRI AUG 28 1998
 
AIR FORCE RECONN OBSERVED DANIELLE DURING THE DAY AND MEASURED
FLIGHT-LEVEL PEAK WINDS OF 88 KNOTS ABOUT 12 NM FROM THE EYE.  THIS
EVENING THE HIGHEST RECONN WIND SPEED AT FLIGHT LEVEL WAS 67 KNOTS
OVER THE NORTHWEST QUAD WITH A MINIMUM CENTRAL PRESSURE OF 989 MB. 
DVORAK SATELLITE ESTIMATES REMAIN BETWEEN 77 AND 90 KNOTS.

THEREFORE DANIELLE INITIAL INTENSITY WILL REMAIN AT 80 KNOTS.  THE
HURRICANE IS FORECAST TO MOVE OVER THIRTY DEGREE CELSIUS WATERS AND
THE SHEAR IS FORECAST TO RELAX.  THE ENVIRONMENT LOOKS FAVORABLE FOR
STRENGTHENING AND THIS IS CONSISTENT WITH THE CURRENT SHIPS
INTENSITY FORECAST AND THE GFDL COUPLED MODELS.  THE OFFICIAL
FORECAST BRINGS DANIELLE TO 100 KNOTS BY 48 HOURS.
 
DANIELLE INITIAL MOTION IS 290/11...A LITTLE SLOWER AND MORE
NORTHERLY THAN PREVIOUSLY.  THE RIDGE NORTH OF DANIELLE IS EXPECTED
TO WEAKEN OVER THE WESTERN ATLANTIC WHILE A STRONG MID-LATITUDE
TROUGH IS FORECAST TO MOVE OVER THE EASTERN UNITED STATES. IN
RESPONSE TO THAT PATTERN...ALL TRACK MODELS REMAIN IN GOOD AGREEMENT
AND CONSISTENTLY TURN DANIELLE NORTHWARD AND NORTH
NORTHEASTWARD AHEAD OF THE TROUGH BEYOND 48 HOURS.  THE EXCELLENT
MODEL AGREEMENT IN TRACK INCREASES THE LEVEL OF CONFIDENCE IN THE
OFFICIAL FORECAST WHICH KEEPS THE HURRICANE AWAY FROM THE EAST COAST
OF THE UNITED STATES.

HPC RAISED A POINT DURING THE CONFERENCE CALL ON THE 18Z AVIATION
RUN OF THE MRF MODEL.  THIS RUN AND THE GUIDANCE DEPENDENT ON IT
TEND TO SLOW THE HURRICANE DURING THE LAST PERIOD.  THE INTERESTING
THING ABOUT THIS 18Z RUN IS THE SPURIOUS VORTEX BEING GENERATED EAST
OF DANIELLE WHICH APPEARS TO BE DISRUPTING THE RIDGE AND THEREFORE
SLOWING THE NORTHWARD PROGRESS OF DANIELLE.  THE OOZ RUN OF THE MRF
MODEL WILL CONTAIN THE JET DROPWINSONDE AND MAY HELP TO RESOLVE THIS
QUESTION.  NO OTHER GLOBAL MODEL SUGGEST THIS SLOWING OF DANIELLE.
 
SORRY...THIS GOT TOO LONG.

GROSS

 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     29/0300Z 24.1N  67.3W    80 KTS
12HR VT     29/1200Z 24.7N  69.0W    85 KTS
24HR VT     30/0000Z 25.8N  71.1W    90 KTS
36HR VT     30/1200Z 27.4N  72.8W    95 KTS
48HR VT     31/0000Z 29.4N  73.5W   100 KTS
72HR VT     01/0000Z 33.7N  72.1W   100 KTS

 
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