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TROPICAL STORM CINDY DISCUSSION NUMBER  18
NATIONAL WEATHER SERVICE MIAMI FL
4 AM EST MON AUG 23 1999

EASTERLY SHEAR CONTINUES TO AFFECT CINDY.  ALTHOUGH IT IS POSSIBLE
THAT THE LOW-LEVEL CENTER HAS RECENTLY BECOME MORE INVOLVED WITH THE
DEEP CONVECTION...WHICH WOULD IMPLY SOME RE-STRENGTHENING...THIS IS
NOT CERTAIN.  THEREFORE THE CURRENT INTENSITY ESTIMATE IS KEPT AT 50
KNOTS.  THE KEY TO THE FUTURE INTENSITY OF CINDY IS THE VERTICAL
SHEAR.  ONCE THE STORM MOVES WEST OF ABOUT 40W LONGITUDE...I.E. MORE
INTO THE LOW-LEVEL EASTERLY TRADEWIND ENVIRONMENT...THE EASTERLY
SHEAR SHOULD DIMINISH SOMEWHAT.  HOWEVER BECAUSE OF OUR LIMITATIONS
IN PREDICTING INTENSITY CHANGE...ONLY SLIGHT STRENGTHENING IS SHOWN
NEAR THE END OF THE FORECAST PERIOD.  

CENTER FIXES FROM TAFB AND SAB ARE SOMEWHAT SOUTH OF THE PREVIOUS
TRACK.  IT IS PRUDENT NOT TO MAKE TO MAKE SIGNIFICANT CHANGES WITH
INFRARED IMAGERY HOWEVER.  BASED ON CONTINUITY...IT IS PRESUMED THAT
THE CENTER IS NEAR THE EAST-NORTHEASTERN EDGE OF THE DENSE OVERCAST.
THIS GIVES AN ESTIMATED INITIAL MOTION OF 285/07...CLOSE TO THAT
FROM THE PREVIOUS ADVISORY.  

THE 00Z AVN RUN OF THE NCEP GLOBAL MODEL SHOWS THE MID-TROPOSPHERIC
SUBTROPICAL RIDGE BUILDING WESTWARD FROM THE EASTERN TO THE CENTRAL
ATLANTIC OVER THE NEXT 2-3 DAYS.  IF THIS VERIFIES...CINDY SHOULD
MAINTAIN A GENERAL WEST TO WEST-NORTHWESTWARD MOTION DURING THE
FORECAST PERIOD.  OBJECTIVE TRACK PREDICTION MODELS GENERALLY SHOW
THIS AS WELL.  THE OFFICIAL FORECAST IS VERY SIMILAR TO THE PREVIOUS
ONE.

PASCH
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     23/0900Z 15.1N  34.9W    50 KTS
12HR VT     23/1800Z 15.4N  36.0W    50 KTS
24HR VT     24/0600Z 15.7N  37.5W    50 KTS
36HR VT     24/1800Z 16.0N  39.5W    50 KTS
48HR VT     25/0600Z 16.5N  42.0W    55 KTS
72HR VT     26/0600Z 17.5N  47.0W    60 KTS
 
 
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