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TROPICAL STORM IVAN DISCUSSION NUMBER  13
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT WED SEP 23 1998
 
IVAN APPEARS ON VISIBLE PICTURES TO BE GETTING BETTER ORGANIZED
AGAIN...WITH THE CENTER UNDER THE CENTRAL AREA OF DEEP CONVECTION
AND A CONVECTIVE BAND TO THE EAST THROUGH NORTH.  T-NUMBERS HAVE
COME UP AGAIN...BUT NOT ENOUGH YET TO BRING THE WINDS ABOVE 45 KT.
THE NNW HEADING CONTINUES WITH THE FORWARD SPEED HAVING INCREASED TO
ABOUT 16 KT.
 
IVAN IS NOW ENTANGLED IN AN UPPER-LEVEL CYCLONIC CIRCULATION.
ANOTHER TROUGH TO THE WEST IS LIKELY TO STEER THE SYSTEM TOWARD THE
NNW AND THEN THE NORTH.  A TURN TOWARD THE NORTHEAST SHOULD OCCUR
NEAR THE END OF THE PERIOD AS THE WESTERLIES GAIN INFLUENCE.  THE
TRACK GUIDANCE SHOWS THIS AND SO DOES THE OFFICIAL FORECAST.  IVAN
COULD BECOME EXTRATROPICAL BY 48 HOURS.
 
RAPPAPORT
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     23/1500Z 29.3N  39.6W    45 KTS
12HR VT     24/0000Z 31.5N  40.5W    50 KTS
24HR VT     24/1200Z 34.2N  40.9W    50 KTS
36HR VT     25/0000Z 36.4N  40.1W    50 KTS
48HR VT     25/1200Z 38.7N  38.3W    50 KTS...EXTRATROPICAL
72HR VT     26/1200Z 42.0N  33.0W    50 KTS...EXTRATROPICAL
 
 
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