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TROPICAL STORM CHANTAL DISCUSSION NUMBER 5
NATIONAL WEATHER SERVICE MIAMI FL
11 AM EDT THU AUG 16 2001

CHANTAL IS MOVING RAPIDLY WESTWARD ABOUT 20 TO 25 KNOTS AROUND THE 
PERIPHERY OF A STRONG MID-LEVEL RIDGE. MOST OF THE AVAILABLE MODELS 
INDICATE THAT THIS RIDGE WILL PERSIST...FORCING CHANTAL ON A GENERAL 
WEST-TO WEST-NORTHWEST TRACK THROUGH THE CARIBBEAN SEA.  A DECREASE 
IN FORWARD SPEED IS EXPECTED BY THE END OF THE FORECAST PERIOD.

THE OVERALL CLOUD PATTERN HAS IMPROVED SINCE YESTERDAY WITH BANDING 
FEATURES AND AN EXCELLENT OUTFLOW. HOWEVER...CONVECTION IS STILL 
SOMEWHAT WEAK NEAR THE CENTER. INITIAL INTENSITY IS 35 KNOTS AND A 
THERE WILL BE BETTER ESTIMATE OF THE MAXIMUM WINDS WHEN THE 
RECONNAISSANCE PLANE CHECKS THE AREA LATER TODAY. THERE IS AN 
UPPER-LEVEL ANTICYCLONE OVER THE SYSTEM THAT GLOBAL MODELS KEEP WITH 
THE TROPICAL CYCLONE. DESPITE THIS APPARENTLY FAVORABLE UPPER-LEVEL 
PATTERN...GLOBAL MODELS WEAKEN THE SYSTEM.  THE GFDL...WHICH 
PREVIOUSLY MADE CHANTAL A HURRICANE IS NOW ALSO WEAKENING IT. WITH 
SUCH FAVORABLE ENVIRONMENT... IT IS REASONABLE TO INDICATE 
STRENGTHENING IN THE OFFICIAL FORECAST. IN THE SHORT TERM...THE 
SHIPS RAPID INTENSIFICATION INDEX SUGGESTS THAT CHANTAL COULD 
QUICKLY REACH HURRICANE STRENGTH.  

NOTE...WITH THE EXCEPTION OF THE FORWARD SPEED OF THE STORM...ALL 
INGREDIENTS APPEAR TO BE PRESENT AT THIS TIME TO HAVE A POTENTIALLY 
DANGEROUS HURRICANE MOVING THROUGH THE WESTERN CARIBBEAN SEA. ALL 
INTERESTS IN THE AREA SHOULD MONITOR THE PROGRESS OF CHANTAL DURING 
THE NEXT FEW DAYS.

FORECASTER AVILA
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     16/1500Z 13.1N  55.3W    35 KTS
12HR VT     17/0000Z 13.5N  59.0W    45 KTS
24HR VT     17/1200Z 14.5N  64.0W    55 KTS
36HR VT     18/0000Z 15.0N  68.0W    65 KTS
48HR VT     18/1200Z 16.0N  72.0W    75 KTS
72HR VT     19/1200Z 17.5N  77.0W    80 KTS
 
 
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