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...FOR INTERGOVERNMENTAL USE ONLY...
TROPICAL STORM ANDREW DISCUSSION NUMBER  13
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT WED AUG 19 1992
 
THE STORM MAY HAVE WEAKENED SOME...IT HAS CERTAINLY BECOME MORE
DIFFICULT TO LOCATE A CENTER.  TSAF AND SAB ARE WITHIN  0.5 DEGREES
OF EACH OTHER AT A LOCATION WHICH RESULTS IN A PAST 12 HOUR MOTION
0F 310/14...WHILE THE RECON AIRCRAFT HAS BEEN UNABLE TO LOCATE A
WELL DEFINED CENTER AT 5000 FT FLIGHT LEVEL AND THE LOWEST SURFACE
PRESSURE FOUND BY THE AIRCRAFT SO FAR IS 1013 MB...UP 8 MB IN SIX
HOURS.
 
OFFICIAL INITAL MOTION IS 305/14.  THE STATISTICAL DYNAMICAL NHC90
AND CLIPER SHOW A TURN TOWARD THE NORTH AND DECELERATION WHILE THE
BAM MODELS AND EARLIER QLM SHOW A MOSTLY WEST NORTHWESTWARD MOTION
WITH DECELERATION.  OFFICIAL TRACK FORECAST IS ADJUSTED SLIGHTLY TO
THE RIGHT OF THE PREVIOUS ADVISORY AND FORWARD MOTION IS UNDER 5
KNOTS AFTER 72 HOURS.  THIS SLOWING DOWN IS A COURSE OF LEAST REGRET
CONSIDERING THE DICHOTOMOUS NATURE OF THE TRACK GUIDANCE MODELS.
 
THE OFFICIAL INITIAL WIND SPEED IS REDUCED SLIGHTLY TO 40 KNOTS
BASED ON THE INFORMATION FROM THE AIRCRAFT.  IN SPITE OF THE CURRENT
WEAKENING TREND...THE AVIATION MODEL 200 MB ANALYSIS AND FORECAST
DOES ALLOW THE POSSIBILITY OF STRENGTHENING DURING THE NEXT THREE
DAYS.
 
LAWRENCE
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     20/0300Z 20.1N  59.8W    40 KTS
12HR VT     20/1200Z 21.5N  61.5W    45 KTS
24HR VT     21/0000Z 23.0N  64.0W    50 KTS
36HR VT     21/1200Z 24.0N  66.0W    50 KTS
48HR VT     22/0000Z 24.8N  67.5W    55 KTS
72HR VT     23/0000Z 25.5N  69.0W    55 KTS