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TROPICAL STORM CHANTAL DISCUSSION NUMBER  12
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT SAT AUG 18 2001
 
SATELLITE SHOWS THAT A LOW-LEVEL CENTER IS MOVING RAPIDLY TO THE
WEST-NORTHWEST AND IS NOW EXPOSED...LEAVING THE MID-LEVEL
CIRCULATION AND MOST OF THE CONVECTION BEHIND.  ON THE OTHER
HAND...A RECONNAISSANCE PLANE HAS FIXED ANOTHER WEAK CENTER A LITTLE
BIT TO THE SOUTH WITH FLIGHT LEVEL WINDS OF 67 KNOTS.  ALL THIS
MEANS THAT CHANTAL HAS BECOME DISORGANIZED WITH AN ELONGATED
CIRCULATION CENTER...VERY DIFFICULT TO LOCATE.  THE POSITION USED AT
THIS TIME IS THE MIDDLE POINT BETWEEN SATELLITE AND RECON WITH AN
INITIAL INTENSITY OF 50 KNOTS.  WITH THIS UNEXPECTED DEVELOPMENT...
IT IS TEMPTING TO FORECAST WEAKENING.  BUT FOR NOW...NO SIGNIFICANT
CHANGE IS FORECAST AT LEAST FOR NEXT 24 HOURS.  CHANTAL COULD EASILY
WEAKEN BACK TO A TROPICAL WAVE...IF THIS TREND CONTINUES.

IN THIS ADVISORY...IT IS ASSUMED THAT CHANTAL WILL SURVIVE AND AN
INTENSIFICATION TREND COULD BEGIN ONCE THE SYSTEM REACHES THE
NORTHWEST CARIBBEAN IN 24 TO 36 HOURS.

THE FORECAST STEERING PATTERN CONTINUES TO CALL FOR A GENERAL
WEST TO WEST-NORTHWEST TRACK THROUGH THE FORECAST PERIOD.  MODELS
HAVE NOT CHANGED FROM EARLIER RUNS...EVENTUALLY BRINGING A TROPICAL 
CYCLONE INTO THE GULF OF MEXICO.
 
FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     18/1500Z 15.0N  73.9W    50 KTS
12HR VT     19/0000Z 16.0N  77.0W    50 KTS
24HR VT     19/1200Z 17.0N  80.0W    50 KTS
36HR VT     20/0000Z 18.0N  82.5W    65 KTS
48HR VT     20/1200Z 19.5N  85.0W    75 KTS
72HR VT     21/1200Z 22.0N  88.5W    65 KTS
 
 
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