Severe Thunderstorm Warning 5, NWS Tallahassee, FL

AREA FORECAST DISCUSSION...UPDATED TO INCLUDE SEVERE TSTM WATCH
NATIONAL WEATHER SERVICE TALLAHASSEE FL
455 AM EST MON JAN 24 2000

UPDATED TO INCLUDE SEVERE THUNDERSTORM WATCH VALID UNTIL 15Z FOR
ALL BUT WALTON COUNTY IN FL CWFA AND SRN TIER OF OUR GA CWFA.

THE 07Z MSAS SURFACE ANALYSIS SHOWED A STATIONARY FRONTAL
BOUNDARY/BAROCLINIC ZONE DRAPED E-W ACROSS SRN PORTION OF CWFA ALONG
A JAX-TLH-DTS LINE. EXTENSIVE BAND OF SHOWERS/EMBEDDED TSTMS COVERED
MUCH OF FL PENINSULA INTO EASTERN GULF IN REGION OF FAVORABLE LIFT
OF RIGHT REAR QUAD 120+ KT JET AND WEAKENING LEAD SHORTWAVE RIDING
ALONG BOUNDARY. 88D MOSAIC REVEALED MOST OF PCPN FROM APALACHEE BAY
SOUTH AND EAST. NEXT UPSTREAM SHORTWAVE INITIALIZED WELL
BY MESO-ETA OVER OK AT 24/00Z NOW OVER AR/LA MOVING ESEWD. RATHER STRONG
UVV FIELD AHEAD OF THIS SHORTWAVE AND LEFT FRONT QUAD OF 140 KT JET
NOSING SEWD INTO LOWER MS VALLEY SPARKING SCATTERED TO NUMEROUS
SHOWERS AND TSTMS FROM CENTRAL AL INTO SRN LA W/ GREATEST
CONCENTRATION OVER SRN MS MOVING EAST AND WILL ENTER OUR WESTERN
CWFA AFTER 08Z.

WINDS INVOF OF BOUNDARY WERE LIGHT/VARIABLE OR CALM...LIGHT E-SE
TO ITS SOUTH AND LIGHT N OVER SE AL/SW GA. MOIST GROUNDS FROM
SUNDAY/S RAINFALL AND LIGHT WINDS HAVE CONTRIBUTED TO FORMATION OF
PATCHY...LOCALLY DENSE FOG OVER PORTIONS OF SE AL/SW GA. ACROSS
THE FL BIG BEND AND EASTERN PANHANDLE...VSBYS RANGED FROM 3 TO P6SM.
THERE WAS 15-20 DEGREE TEMP SWING ACROSS THE BOUNDARY W/ 45 AT ABY
TO 62 AT AQQ.

MODELS IN GOOD AGREEMENT W/ REGARDS TO POSITION/INTENSITY OF POTENT
MID/UPPER LEVEL SHORTWAVE TROUGH OVER LOWER MS VALLEY WHICH IS PROGGED
TO ZIP ACROSS THE SOUTHERN GULF COAST STATES TODAY AND EXIT THE FL
PENINSULA LATER TONIGHT. ASSOCIATED CYCLOGENESIS AND FAVORABLE JET
DYNAMICS/LIFT ALONG BAROCLINIC ZONE OVER NORTH FL WILL AID IN THE
ENHANCEMENT OF CONVECTION ACROSS THE CWFA TODAY. ETA...NGM...AND RUC
ALL PROG THE MAIN VORTICITY MAX TO SWING EWD ACROSS THE FL PANHANDLE
THIS MORNING AND NORTH FL THIS AFTERNOON. BEST LI/S ON NGM (0 TO -2)
INDICATE CONTINUED CHC FOR SOME TSTMS EVEN THOUGH SFC BASED LIS ARE
MARGINAL AT BEST. ATTM...BEST INSTABILITY/HIGHEST CAPES OFFSHORE AND
EXPECT STRONGER CONVECTION IN THIS AREA. LATEST SWOMCD FROM SPC ADDRESSES
THIS AND POSSIBILITY OF STRONG TO SEVERE TSTMS ALONG COASTAL BEND.
WILL CONTINUE TO MONITOR CLOSELY.

ONCE SHORTWAVE AND SURFACE LOW MOVE EAST OF CWFA THIS AFTERNOON...FRONT
WILL PUSH SEWD INTO SOUTH FL BY 25/00Z...AND EAST OF FL BY 25/12Z.
BROAD LONGWAVE TROUGH WILL MAINTAIN NORTHWESTERLY FLOW IN MID/UPPER
LEVELS THRU 48 HRS. THE SURFACE PRESSURE GRADIENT ACROSS THE
FORECAST AREA TIGHTENS THIS AFTERNOON AND TONIGHT BETWEEN DEPARTING
SURFACE LOW TO THE EAST AND HIGH PRESSURE BUILDING EWD FROM SOUTHERN
PLAINS. MEAN 1000-500 RH VALUES DECREASE FROM WEST TO EAST LATER THIS
AFTERNOON AND EVENING ALONG W/ CLEARING TREND. NORTH TO NORTHWEST
WINDS INCREASE AREAWIDE BY LATE MORNING IN WAKE OF SURFACE LOW AND
WILL USE "BRISK" WORDING ALL ZONES. WINDS GRADUALLY DIMINISH LATER
THIS EVENING. CLOUD COVER/PCPN SHOULD KEEP TEMPS IN 50S TODAY. DRIER
AIRMASS FILTERS IN AND GOOD RADIATIONAL COOLING SETUP FOR MIN TEMPS
TUE IN LOW-MID 30S...UPR 30S IMMEDIATE COAST. PLENTY OF LOW LEVEL
COLD AIR ADVECTION DESPITE FAIR-GOOD INSOLATION TUE TO KEEP MAXIMA
IN 50-55 DEG RANGE.

WITH PROXIMITY OF FRONTAL BOUNDARY...STRONG UPPER LEVEL DYNAMICS
SWINGING EAST THRU THE CWFA AND DEVELOPING SURFACE LOW...CATEGORICAL
POPS THIS MORNING...ENDING BY 15Z DHN/PFN...18Z ABY/TLH...AND
21Z VLD/CTY. NIL POPS TONIGHT/TUE. FAN MOS APPEARS A TAD COOL AND
WILL STAY CLOSE TO FWC.

FIRE WEATHER: NO CONCERNS TODAY DUE TO CLOUDS/PCPN/HIGH RH. DEWPTS
FALL INTO THE 20S TUE AFTERNOON INLAND ZONES W/ AFTERNOON
MAXIMA IN 50-55 DEG RANGE...RESULTING IN LOWEST RH VALUES NEAR 30
PERCENT. STILL SOME UNCERTAINTY AS TO HOW LOW DEWPTS WILL DROP W/
NGM THE DRIEST AND ETA/AVN MAINTAINING LOW-MID 30S. WILL PALY IT
SAFE AND POST FIRE WEATHER WATCH FOR TUE AFTERNOON THRU SUNSET.

EXTENDED: AFTER FREEZING TEMPS TUE NIGHT...EXPECT P/CDY AND COLD
WED/THU...THEN INCREASING CLOUDS...SLIGHT WARMING AND CHANCE OF
SHOWERS FRI WITH LOW PRESSURE/COLD FRONT APPROACHING FROM LOWER MS
VALLEY. LOWS IN 20S WED/THU...WARMING TO 30S FRI. HIGHS AROUND 50
WED/THU AND IN 50S FRI.

MARINE: TPA W (42036) BUOY OBSERVED EAST 15 GUST 17 KT WHILE WINDS
AT PNS S (42039) HAVE VEER TO THE SOUTH AS LOW PRESSURE APPROACHES
FROM WEST. SPEEDS HAVEN/T INCREASED AS EXPECTED EARLY THIS MORNING
W/ 8-10 KT AND 4 FT SEAS. ANTICIPATE WIND SHIFT TO WEST THEN NORTHWEST
AND SPEEDS/SEAS INCREASING TO SMALL CRAFT ADVISORY CRITERIA BY
AFTERNOON...CONTINUING TONIGHT. WINDS/SEAS GRADUALLY SLACKEN TUE AS
HIGH PRESSURE RIDGE EDGES EAST INTO MARINE AREA AND SURFACE PRESSURE
GRADIENT RELAXES.

THANKS FOR COORDINATION MOB. COMMENTS WELCOME.

PRELIM CCF...

TLH 058/033 054/027 8000
PFN 057/039 054/035 8000
DHN 050/033 052/028 8000
ABY 049/033 051/027 8000
VLD 059/034 052/029 8-00

.TLH...
AL...NONE.
GA...SEVERE TSTM WATCH UNTIL 15Z GAZ155>161.
FL...SEVERE TSTM WATCH UNTIL 15Z FLZ009>019-026>029-034.
     SMALL CRAFT ADVISORY SUWANNEE RIVER TO DESTIN.
     FIRE WEATHER WATCH TUE AFTERNOON INLAND FL ZONES.

MAJ