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TROPICAL STORM DANIELLE DISCUSSION NUMBER   4
NATIONAL WEATHER SERVICE MIAMI FL
4 AM EST TUE AUG 25 1998

DANIELLE HAS A SYMMETRIC APPEARANCE IN SATELLITE IMAGERY WITH 
GOOD OUTFLOW OVER THE WESTERN SEMICIRCLE.  THERE HAS BEEN A 
RATHER PERSISTENT AREA OF DEEP CONVECTION NEAR THE CENTER OF
DANIELLE OVER THE LAST 4-6 HOURS.  DVORAK INTENSITY ESTIMATES
FROM TAFB AND SAB ARE 3.5 AND 2.5...RESPECTIVELY.  THE INITIAL
INTENSITY IS INCREASED TO 45 KNOTS FOR THIS ADVISORY.  

MODEST SOUTH/SOUTHWESTERLY SHEAR SEEN IN SATELLITE IMAGERY...AND 
IN ANALYSES FROM THE COOPERATIVE INSTITUTE FOR METEOROLOGICAL
SATELLITE STUDIES...IS ASSOCIATE WITH AN UPPER-LEVEL LOW SEEN IN
WATER VAPOR IMAGERY BETWEEN DANIELLE AND THE LESSER ANTILLES. THIS
LOW IS FORECAST TO MOVE WESTWARD DURING THE NEXT COUPLE OF 
DAYS.  GRADUAL STRENGTHENING IS FORECAST ALTHOUGH DANIELLE MAY
EXPERIENCE SOME VERTICAL SHEAR DURING THE NEXT 24-36 HOURS. BY
48 HOURS DANIELLE IS BROUGHT TO HURRICANE STRENGTH AS THE SHEAR
IS FORECAST TO DIMINISH.   
 
THE INITIAL MOTION ESTIMATE IS 285/18 KNOTS.  THE 00Z AVIATION
MODEL CONTINUES TO SUGGEST THAT A RIDGE WILL BUILD OVER THE 
WESTERN ATLANTIC NORTH OF THE LESSER ANTILLES.  THIS WOULD RESULT
IN A CONTINUED WEST-NORTHWEST MOTION THROUGH THE PERIOD WITH 
POSSIBLE A MORE WESTWARD HEADING BEYOND 72 HOURS.  THE GFDL SHOWS
THIS TYPE OF SCENARIO AND IS THE LEFT-MOST OF THE 06Z TRACK MODEL
GUIDANCE.  THE OFFICIAL FORECAST TRACK IS A LITTLE RIGHT OF THE 
GFDL TRACK AND IS VERY SIMILAR TO THE PREVIOUS PACKAGE.
 
GUINEY
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     25/0900Z 15.7N  42.4W    45 KTS
12HR VT     25/1800Z 16.4N  45.2W    50 KTS
24HR VT     26/0600Z 17.2N  48.7W    55 KTS
36HR VT     26/1800Z 17.9N  52.4W    60 KTS
48HR VT     27/0600Z 18.5N  56.0W    65 KTS
72HR VT     28/0600Z 19.0N  63.5W    75 KTS
 
 
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