Severe Thunderstorm Warning 88, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
205 PM EDT FRI JUL 20 2001

.CURRENTLY...LATEST MSAS SHOWS E-W SURFACE RIDGE OVER THE GULF. A
BACKDOOR FRONT EXTENDS FROM LOW PRESSURE OVER ERN KY SWD THRU ERN
GA. AREA 88DS BECOMING ACTIVE W/ SCT SHOWERS & TSTMS DEVELOPING FROM
E/SE AL INTO CNTRL/SW GA & MOVING SWD...WHILE SEA BREEZE CONVECTION
FIRING ALONG THE TAYLOR-DIXIE COUNTY COASTLINE. VISIBLE
SATELLITE/METARS INDICATE PARTLY-MOSTLY SUNNY SKIES W/ AREAS OF
HAZE. TEMPS WERE QUITE WARM OUTSIDE RAIN AREAS W/ READINGS IN THE
LOW-MID 90S. DEWPTS IN THE 70S CREATED HEAT INDICES FROM 95-105
DEGREES. WINDS WERE NWLY UNDER 10 MPH...BUT VARIABLE & GUSTY INVOF
TSTMS.

.MODELS/ZONE FCST...12Z MODELS IN GENERAL AGREEMENT W/ SYNOPTIC
FEATURES. IN THE MID/UPPER LEVELS...MEAN RIDGE OVER CNTRL CONUS
RETROGRADES SLIGHTLY TOWARD THE LATTER HALF OF THE 48-HR PERIOD AS
SHORTWAVE ENERGY CONTINUES TO CREST THE RIDGE & RIDE SSWD INTO THE
SERN CONUS...MAINTAINING TROUGHINESS OVER THE CWFA. AT THE
SURFACE...THE BACKDOOR FRONT FROM ERN KY TO ERN GA MOVES INTO OUR GA
CWFA TONIGHT AS HIGH PRESSURE RIDGES SWD INTO THE CAROLINAS. THE
FRONT CONTINUES ITS SWD PROGRESSION INTO THE FL ZONES SATURDAY AS
DEVELOPING LOW PRESSURE OVER GA MOVES INTO N FL. ETA APPEARS TO BE
THE MOST AGGRESSIVE & FURTHEST S AS LOW & COLD FRONT PROGGED JUST S
OF CTY...NGM HAS LOW & FRONT NEAR THE FL PNHDL & BIG BEND
COASTS...AND AVN IN BETWEEN. AN INTERESTING FCST NONETHELESS. AMPLE
CLOUD COVER & A FRONT IN THE VICINITY SHOULD NEGATE THE SEA BREEZE
THIS WEEKEND. NGM/AVN TIME-HEIGHT CROSS-SECTIONS PORTRAY DEEP LAYER
MOISTURE OVER THE CWFA THRU SAT NIGHT...WHILE THE ETA ADVECTS
IN DRIER AIR AT THE MID/UPPER LEVELS BY SATURDAY AFTN. HAVE
DISCOUNTED THE ETA ALL TOGETHER & WILL LEAN TOWARD A COMPROMISE OF
THE AVN & NGM. LITTLE CHANGE FROM CURRENT ZONE PACKAGE W/ CHANCE
POPS BOTH NIGHTS & FROM GOOD CHANCE AL/GA ZONES TO LIKELY FL ZONES
SATURDAY. SLIGHTLY DRIER AIR FILTERS INTO AL/GA ZONES BEGINNING
SATURDAY NIGHT & CONTINUING SUNDAY. HAVE LOWERED POPS TO CHANCE
THERE SUNDAY & KEPT GOOD CHANCE FOR FL ZONES IN CLOSER PROXIMITY TO
FRONT. USED AN AVERAGE OF MAV/FAN TEMPS.

.EXTENDED...MRF/AVN SHOW CNTRL CONUS RIDGE CONTINUING TO RETROGRADE
TOWARD THE 4-CORNERS REGION EARLY NEXT WEEK AS TROUGHINESS LINGERS
OVER THE ERN CONUS. BY MID-WEEK...RIDGE OVER THE WRN ATLANTIC
EXTENDS WWD ACROSS THE SRN CONUS. THE BERMUDA RIDGE BUILDS WWD
ACROSS FL PENINSULA INTO THE GULF. THE UPSHOT IS A MEAN S-SW LOW
LEVEL FLOW WHICH FAVORS 30-50% COVERAGE OF SEA BREEZE-GENERATED
AFTN/EVE CONVECTION & CLIMO TEMPS.

.MARINE...W WINDS TONIGHT SHIFT TO NW SATURDAY AS FRONT EDGES INTO
THE NEAR SHORE WATERS. NW WINDS SATURDAY NIGHT BECOME N SUNDAY AS
LOW PRESSURE MOVES TOWARD NE FL COAST & DRAGS BOUNDARY THRU
REMAINDER OF MARINE AREA. HIGH PRESSURE RIDGE BUILDS N OF THE WATERS
SUNDAY NIGHT & MONDAY W/ NE WINDS. WINDS REMAIN BELOW SCEC CRITERIA
THRU THE PERIOD.

.FIRE WEATHER...NO CONCERNS.

.PRELIM CCF...
TLH TT 074/090 074/090 4645
PFN TT 078/088 077/087 4645
DHN TE 075/090 074/089 4533
ABY TE 074/089 074/088 4533
VLD TE 074/090 074/089 4544 08

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

MAJ