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TROPICAL DEPRESSION CHANTAL DISCUSSION NUMBER 27
NATIONAL WEATHER SERVICE MIAMI FL
5 AM EDT WED AUG 22 2001
CHANTAL REMAINS OVER LAND NEAR THE GULF OF MEXICO COAST OF WESTERN
YUCATAN. THE LOW-LEVEL CENTER IS LOCATED ABOUT 40 NM ENE OF CARMEN
MEXICO...WHILE A MID-LEVEL CIRCULATION THAT TRACKED NORTHWESTWARD
OUT OF NORTHERN GUATEMALA IS LOCATED OVER CARMEN. MEANWHILE...DEEP
CONVECTION HAS REDEVELOPED FARTHER EAST OVER BELIZE AND EASTERN
YUCATAN. NEEDLESS TO SAY...CHANTAL REMAINS POORLY ORGANIZED.
A ROUGH ESTIMATE OF THE INITIAL MOTION IS 280/7...BASED MAINLY ON
EXTRAPOLATION FROM THE PREVIOUS FORECAST TRACK AND NIGHTTIME VISIBLE
SATELLITE IMAGERY. A LARGE SPREAD IN THE GUIDANCE AFTER 24 HOURS
HAS CONTINUED WITH THE 06Z MODEL RUNS. THE GFDL NOW TAKES CHANTAL
OVER THE GULF AND THEN NORTHWARD TO NEAR TAMPICO IN 72 HOURS...
WHILE THE AVN AND UKMET MODELS DRIVE THE CYCLONE WEST INTO THE GULF
THROUGH 24 HOURS AND THEN TURN CHANTAL SOUTHWARD INTO MEXICO
AFTERWARDS. WATER VAPOR IMAGERY INDICATES THE DIGGING MID- AND
UPPER-LEVEL TROUGH OVER THE WESTERN AND SOUTHERN GULF OF MEXICO HAS
BOTTOMED OUT NOW. HOWEVER...THE LOW-LEVEL RIDGING BENEATH THE UPPER
TROUGH SHOULD STILL BE STRONG ENOUGH TO KEEP CHANTAL ON A GENERAL
WESTWARD TRACK THROUGH AT LEAST 36 HOURS. THE NORTH TO NORTHEASTERLY
MID- AND UPPER-LEVEL FLOW SHOULD HELP TO DRIVE THE CYCLONE TO THE
SOUTHWEST AND INLAND IF CHANTAL RE-INTENSIFIES AND BECOMES A
VERTICALLY DEEP SYSTEM AGAIN. THE OFFICAL FORECAST IS BETWEEN THE
PREVIOUS FORECAST TRACK AND THE AVN-UKMET CONSENSUS TRACK.
WATER VAPOR IMAGERY INDICATES THAT THE NORTHERLY DRY AIR INTRUSION
OVER THE BAY OF CAMPECHE TO THE NORTH AND WEST OF CHANTAL HAS
STARTED TO PUSH MORE WESTWARD. THIS MAY ALLOW FOR SOME OF THE
DEEPER MOISTURE OVER THE YUCATAN AND NW CARIBBEAN SEA TO MOVE
WESTWARD INTO THE BAY OF CAMPECHE...WHICH WOULD FAVOR THE
RE-DEVELOPMENT OF DEEP CONVECTION ONCE THE LOW-LEVEL CENTER MOVES
BACK OVER WATER. HOWEVER...THE INTENSITY FORECAST IS DEPENDENT ON
WHERE THE CENTER OF CHANTAL ACTUALLY TRACKS. IF IT REMAINS CLOSER
TO LAND...THEN ANY SIGNIFICANT RE-INTENSIFICATION WILL BE UNLIKELY.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 22/0900Z 19.0N 91.2W 25 KTS...INLAND
12HR VT 22/1800Z 19.1N 92.2W 30 KTS
24HR VT 23/0600Z 19.1N 94.0W 35 KTS
36HR VT 23/1800Z 18.7N 95.0W 45 KTS
48HR VT 24/0600Z 17.7N 95.3W 25 KTS...INLAND AND DISSIPATING
72HR VT 25/0600Z...INLAND AND DISSIPATED
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