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TROPICAL STORM CHANTAL DISCUSSION NUMBER 22
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT MON AUG 20 2001
REPORTS FROM AN AIR FORCE RECONNAISSANCE AIRCRAFT THIS EVENING SHOW
THAT CHANTAL WAS STRENGTHENING RIGHT UP UNTIL LANDFALL. A NOAA P-3
RESEARCH MISSION WAS ALSO VERY HELPFUL THIS EVENING...RELEASING
NUMEROUS GPS DROPWINDSONDES IN THE IMMEDIATE VICINITY OF CHANTAL. A
SONDE IN THE CONVECTION NORTHEAST OF THE CENTER AT 2144Z GAVE 58 KT
AT THE SURFACE...AND THE PEAK FLIGHT LEVEL WIND WAS 71 KT. THESE
OBS SUPPORT SURFACE WINDS OF 60 KT. RIGHT AT LANDFALL...AND SHORTLY
AFTER THE AIRCRAFT LEFT THE STORM...THERE WAS A BURST OF DEEP
CONVECTION VERY CLOSE TO THE CENTER. ONE COULD SPECULATE THAT
CHANTAL CONTINUED TO STRENGTHEN AFTER THE LAST FIX...BUT IT IS
UNLIKELY THAT ANY SOLID DATA SUPPORTING A HIGHER INTENSITY WILL
COME TO LIGHT.
THERE HAS BEEN LITTLE CHANGE TO THE FORECAST PHILOSOPHY. BOTH THE
AVN AND UKMET GLOBAL MODELS FORECAST A FAVORABLE UPPER-LEVEL
ENVIRONMENT IN THE SOUTHERN GULF OF MEXICO. HOWEVER...WATER VAPOR
IMAGERY SHOWS AN UPPER-LEVEL TROUGH DIGGING SOUTHWARD IN THE WESTERN
GULF OF MEXICO. GIVEN THIS...AND THE RECENT TENDENCY OF THE GLOBAL
MODELS TO BE TOO ENTHUSIASTIC IN DEVELOPING THE UPPER ANTICYCLONE
OVER THE STORM...I AM NOT VERY CONFIDENT THAT CHANTAL WILL
RESTRENGTHEN AS INDICATED BY THE OFFICIAL FORECAST.
FORECASTER FRANKLIN
FORECAST POSITIONS AND MAX WINDS
INITIAL 21/0300Z 18.4N 88.3W 60 KTS...INLAND
12HR VT 21/1200Z 19.0N 90.0W 40 KTS...INLAND
24HR VT 22/0000Z 19.6N 91.8W 45 KTS
36HR VT 22/1200Z 20.1N 93.3W 50 KTS
48HR VT 23/0000Z 20.5N 95.0W 55 KTS
72HR VT 24/0000Z 21.0N 97.5W 65 KTS...INLAND
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