Severe Thunderstorm Warning 91, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
240 PM EDT SAT AUG 18 2001

AT 18Z...SHOWERS AND THUNDERSTORMS BECOMING MORE ACTIVE OVER THE
FLORIDA ZONES WITH VERY LITTLE ACTIVITY NORTH OF THE FLORIDA BORDER.
VERY MUGGY OUT WITH METARS SHOWING DEW POINTS IN THE MID TO UPPER
70S. ALBANY CURRENTLY HAS A TEMP/DEW POINT OF 90/77 MAKING IT FEEL
LIKE 103 DEGREES. THE AIRMASS IS VERY MOIST AND UNSTABLE AND FEEL IT
IS ONLY A MATTER OF TIME BEFORE WE SEE THUNDERSTORMS FIRE ACROSS OUR
SE AL AND GA ZONES.

MODELS: IN THE UPPER LEVELS...SHORT WAVE ROTATES AROUND THE GREAT
LAKES REGION WITH A DEEPENING TROUGH SWINGING INTO THE SOUTHEASTERN
STATES THROUGH THE SHORT TERM PERIOD. THIS WILL SEND A COLD FRONT
TOWARD THE CWA BY 12Z MON AND NOW APPEARS WILL NOT PUSH THROUGH
UNTIL OVERNIGHT MONDAY/TUESDAY MORNING. THE NGM AND AVN ARE IN
PRETTY GOOD AGREEMENT ON THE MOISTURE FIELDS AND PLACING FRONT
ACROSS THE CENTRAL CAROLINAS SOUTHWEST THROUGH SOUTH CENTRAL ALABAMA
MONDAY MORNING. THE ETA ON THE OTHER HAND SHOWS THE FRONT LAGGING
BEHIND OVER NORTHERN GEORGIA AND ALABAMA WITH BENIGN MOISTURE
FIELDS. BY 00Z TUESDAY...THE AVN SHOWS THE FRONT A LITTLE FURTHER
SOUTH BUT STILL STAYING NORTH OF THE FA. HOWEVER...SOME MID AND
UPPER DRYING DOES ENTER AT LEAST OUR NORTHERN GA AND SE AL ZONES
MONDAY AFTERNOON AND EVENING. THE 1000-700MB MEAN FLOW WILL CONTINUE
TO BE WEST TO SOUTHWEST 10 TO 15 KNOTS THE NEXT TWO DAYS. FOR OUR
SEA BREEZE CLIMATOLOGY...THIS WOULD SUPPORT CHANCE POPS THROUGHOUT
OUR ZONES AND MODEL POPS SUPPORT THIS. FORECAST AVN/NGM SOUNDINGS
SHOW PW NEAR OR OVER 2.00 INCHES THROUGH MONDAY EVENING ACROSS THE
EASTERN ZONES WITH PW DROPPING DROPPING TO AROUND 1.4 TO 1.6 AT DHN
AND ABY RESPECTFULLY. WILL TAPER POPS DOWN SLIGHTLY FOR SE AL AND A
PORTION OF GA FOR MONDAY. WILL USE MAV/FWC AVERAGE FOR TEMPERATURES.

MARINE: WINDS SHOULD REMAIN OUT THE WEST TO SOUTHWEST THROUGH THE
SHORT PERIOD AT 15 KNOTS OR LESS WITH SEAS IN THE 1 TO 3 FOOT RANGE.
BEYOND MONDAY THE FORECAST IS VERY UNCERTAIN DUE TO THE POSSIBILITY
OF CHANTAL ENTERING THE EASTERN GULF. THE AVN AND MRF SHOW THE
SYSTEM MOVING THROUGH THE YUKATAN CHANNEL TUESDAY MORNING AND THEN
TAKING ON A NORTH TO NORTHWEST COURSE TOWARD NEW ORLEANS. WILL SHOW
WINDS VEERING AROUND TO THE EAST THEN SOUTHEAST IN THE EXTENDED
PERIOD BUT KEEP WINDS AND SEAS DOWN AT THIS TIME.

EXTENDED: THE AVN SHOWS THE FRONT PUSHING THROUGH ALL BUT OUR
EASTERN BIG BEND ZONES BY TUESDAY EVENING WITH SIGNIFICANT MID AND
UPPER LAYER DRYING BEHIND THE FRONT. ALSO AT THIS TIME...THE AVN
PLACES CHANTAL IN THE SOUTHEASTERN GULF (SOUTH OF PENSACOLA AND WEST
OF NAPLES). HOWEVER...THE OFFICIAL NHC 72H FORECAST POSITION IS
FURTHER SOUTH AND WITH A WNW HEADING. THUS..FOR NOW WILL LEAVE
EXTENDED PACKAGE WORDING THE SAME.

PRELIMINARY NUMBERS:

TLH 074/091 074/091 3535
PFN 078/088 077/088 3535
DHN 074/090 073/089 3534
ABY 074/091 073/090 3534
VLD 075/092 074/092 3535

.TLH...
AL...NONE.
GA...NONE.
FL...NONE.

BARRY