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TROPICAL STORM ALEX DISCUSSION NUMBER  18
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT FRI JUL 31 1998
 
YESTERDAY...WE FORECAST THAT ALEX WAS GOING TO REACH HURRICANE
STATUS IN ABOUT 48 HOURS.  INSTEAD...STRONG SOUTHERLY UPPER-LEVEL
WINDS HIT THE STORM REMOVING MOST OF THE CONVECTION FROM THE LOW-
LEVEL CENTER AND CONSEQUENTLY...WEAKENING HAS OCCURRED.  THIS
WEAKENING WAS NOT INDICATED BY ANY OF THE AVAILABLE TOOLS AND
REFLECTS HOW LITTLE WE KNOW ABOUT FORECASTING INTENSITY CHANGES.
AFTER THE FACT....IT IS SOMETIMES EASY TO FIND AN EXPLANATION.

IT APPEARS THAT THE WIND SHEAR WILL PERSIST SO WEAKENING SHOULD
CONTINUE AND ALEX COULD BE DOWNGRADED TO A TROPICAL DEPRESSION
TONIGHT OR SATURDAY.   INITIAL INTENSITY HAS BEEN ADJUSTED TO 35
KNOTS AND WINDS ARE KEPT AT 30 KNOTS THROUGH 72 HOURS.  

NOW THAT WE CAN SEE THE LOW LEVEL CENTER...WE HAVE A BETTER ESTIMATE
OF THE INITIAL MOTION WHICH IS 280/10.  A GRADUAL TURN TO THE WEST-
NORTHWEST AND NORTHWEST IS EXPECTED OF WHATEVER IS LEFT OF ALEX.
HOWEVER...IF IT BECOMES AN OPEN WAVE THE SYSTEM WILL PROBABLY
PROPAGATE WESTWARD SPREADING SHOWERS AND SQUALLS. 

THE NOAA HIGH ALTITUDE JET HAS BEGUN TO SAMPLE THE ENVIRONMENT
SURROUNDING ALEX.  

AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     31/2100Z 15.8N  51.1W    35 KTS
12HR VT     01/0600Z 16.0N  52.6W    30 KTS
24HR VT     01/1800Z 17.0N  55.0W    30 KTS
36HR VT     02/0600Z 19.5N  57.0W    30 KTS
48HR VT     02/1800Z 20.5N  59.0W    30 KTS
72HR VT     03/1800Z 24.0N  62.5W    30 KTS
 
 
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