Severe Thunderstorm Warning 121, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
230 PM EDT FRI JUL 19 2002

CURRENTLY: MOSTLY SUNNY TO SUNNY SKIES ACROSS THE LOCAL AREA. CLOUDS
3-6K. ITS HOT AND HUMID...TEMPS 95 TO 100 (PANAMA CITY) AND DEW
POINTS 69-75. HEAT INDICES RANGING FROM 101 TO 110 (CROSS CITY). 24
HR TEMP/DEW POINT PLOT SHOW LITTLE CHANGE IN THE LOCAL AIR MASS.
RADAR INDICATED THAT ISOLD SHOWERS AND THUNDERSTORMS WERE DEVELOPING
ACROSS THE FLA BIG BEND SEA BREEZE FRONT ESPECIALLY IN DIXIE AND
TAYLOR COUNTIES AND WILL SPREAD THRU THE AFTERNOON.

DISCUSSION: LOOKING AT THE BIG PIX...SUMMERTIME WEAK FLOW PATTERN
PERSISTS ACROSS MOST OF CONUS. MAIN MID-UPR FEATURES ARE LOW LIFTG
NE OVER NEVADA...DOWNSTREAM STRONG HIGH REMAING ACROSS CNTRL HI
PLAINS WITH MID/UPR RIDGE EXPANDING EWD AS IT DOMINATES CNTRL
CONUS. WEAK UPR TROF OVR MID MS VALLEY TO MOVE SLOWLY SE. FURTHER
DOWNSTREAM...DEEPENING UPR TROF ACROSS SE CANADA INTO NE CONUS TO
MOVE OFFSHORE. ASSOCD COLD FRONT MOVG ESE TO N ENGLAND AND NRN
MID-ATLC STATES AND SRN GREAT LAKES. ANOTHER WEAK BOUNDARY STALLED
OVR MID MS/TN RIVER VALLEYS NW INTO NRN PLAINS/MID MO RIVER VALLEY.
THUS NORTHEAST...NRN ROCKIES/INTERMOUNTAIN/NRN HI PLAINS/MID
MO/MS/TN RIVER VALLEYS FOCUS OF CONVECTION. AS MID MS VALLEY MOVES
SE INTO TENN VALLEY WITH SOME ASSOCD ENERGY EJECTG FURTHER
SWD...CONVECTION FOCUS SHIFTS TO SE.

LOCALLY...CURRENT WEATHER GOOD INDICATOR THAT WE ARE CHANGING FROM
VERY HOT AND DRY PATTERN TO A MORE HUMID/NORMAL SUMMER ONE. UPPER HI
ACROSS LOCAL AIR SHOWING SIGNS OF FLATTENING IN RESPONSE TO ABOVE
MENTIONED MID MS VALLEY SHORT WAVE. AS SHORT WAVE DIGS DEEPER
TOMORROW SWEEPING PVA AND DIVERGENCE INTO ALA/GA...UPR DYNAMICS
INCRS ESPECIALLY OVR OUR NRN ZONES. AT LWR LEVELS...1000-700 MB
STEERING FLOW SHIFTS FROM LGT NLY TO SW (TYPE 5) WHICH IS A
FAVORABLE PRECIP REGIME...ESPECIALLY FOR SEA BREEZE PENETRATION INTO
PANHANDLE/BIG BEND COASTAL COUNTIES. VAD...TIME-HGHT X-SECTIONS AND
MODEL SOUNDINGS RESPOND WITH INCREASG OMEGA...DEEP LYR MOISTURE...
HIGHER PWATS AND CAPES AND COOLING ALOFT SAT AND THEN FURTHER INTO
SUNDAY AND MONDAY. THIS WILL ALSO RESULT IN INCRESD CLOUDS AND A
SLOW COOLING (2-4 DEGREES EACH DAY IN MAX/MINS...LESS SO ACROSS FLA
WHERE WLY SURFACE FLOW WILL BE SLOWER TO SHIFT) AND BRING WELCOME
END TO HEAT INDICES ABOVE 100 DEGREES.

FORECAST: 4 ZONE ZFP WITH 20 PCT POPS TONGIHT AND 40-50 PCT POPS
TOMORROW. WITH MINOR COOLING TOMORROW..WE SHUD REMAIN BLO RECORD
TEMPS (SEE BELOW). 50 PCT POPS SAT AND SUNDAY.

EXTENDED (TUESDAY THROUGH FRIDAY): LITTLE CHANGE. SCT POPS AND
RETURN TO CLIMO TEMPS.

ALL TIME RECORD TEMPS
             JULY 19TH   JULY 20TH
TALAHASSEE   103  2000   100 2000
APALACHICOLA  99  2000    98 1942
PANAMA CITY   98  2000   101 2000
CROSS CITY    99  1983    97 2000
PERRY         98  1986    99 1986
ALBANY       104  1913   103 1915
QUITMAN/VLD  102  1915   102 1942
DOTHAN AREA  106  2000   105 2000

PRELIMINARY NUMBERS...
TLH 076/095 075/094 2425
PFN 079/092 078/090 2425
DHN 076/095 075/094 2525
ABY 075/095 075/094 2525
VLD 075/096 074/094 2425

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

BLOCK