Lightning Strike in Florida, January 20, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
920 PM EST WED JAN 20 2010

.SHORT TERM...LATEST MSAS ANALYSIS SHOWS AN INCREASING GRADIENT
ACROSS THE AREA AS HIGH PRESSURE CONTINUES TO MOVE OFFSHORE AND
LOW PRESSURE STRENGTHENS OVER THE CENTRAL PLAINS. SOUTHERLY FLOW
NOW PRESENT OVER THE ENTIRE PENINSULA WITH HPC WARM FRONTAL
POSITION WELL NORTH OF THE AREA. THERE REMAINS HOWEVER A
SIGNIFICANT DEWPOINT DISCONTINUITY OVER THE PENINSULA AND
ADJACENT GULF WITH LOWER 50S OVER WEST CENTRAL FLORIDA AND LOWER
70S OVER THE WATERS. THIS IN AND OF ITSELF WOULD BE ENOUGH TO
GENERATE AN OVERRUNNING LOW LEVEL PROFILE TONIGHT...BUT WE ALSO
HAVE MORE SUBSTANTIAL ISENTROPIC PROCESSES FURTHER ALOFT IN THE
ATMOSPHERE. DEVELOPING 40 KT FLOW AT 4K FEET WILL GENERATE
ADIBATIC OMEGA THROUGH 15K FEET OF A SATURATED COLUMN. THIS IS
ALREADY TAKING PLACE OVER WESTERN ZONES AND WILL QUICKLY SPREAD
NORTHEAST TONIGHT. CURRENT POP GRIDS LOOK ON TRACK AS FAR AS
OVERALL DISTRIBUTION...BUT WILL NEED TO BUMP UP TIMING SLIGHTLY
BASED ON RECENT RADAR TRENDS.

JAX SOUNDING TONIGHT SHOWS INVERSION CLOSE TO 700 MB BUT A FAIRLY
UNSTABLE PROFILE ABOVE THAT. ISENTROPIC PROCESSES SHOULD ALLOW FOR
DEVELOPING CORES IN THE UNSTABLE LAYER TONIGHT WITH SCT
THUNDERSTORM DEVELOPMENT AFTER MIDNIGHT. -14C AT 500 MB WILL MAKE
HAIL THE PRIMARY THREAT INITIALLY AS WINDS WILL HAVE A VERY TOUGH
TIME MAKING IT DOWN THROUGH STABLE LAYER. EVEN AS THE PRIMARY
THREAT...FEEL HAIL POTENTIAL WILL BE MINIMAL AS IT WILL BE
DIFFICULT TO GENERATE THE NEEDED UPDRAFT IN CURRENT PROFILE.

STILL LOOK ON TRACK FOR THE MAIN SEVERE THREAT ALONG DEVELOPING
SQUALL LINE THROUGH THU AFTERNOON. BASED ON RECENT TRENDS...IT
LOOKS AS THOUGH DEBRIS CLOUDS AND PRECIP MAY REMAIN NORTH OF OUR
SOUTHERN MOST COUNTIES ALLOWING FOR MORE DESTABILIZATION AND
POTENTIALLY 1500+ CAPE VALUES. WILL BE POSTING ANOTHER WEB
BRIEFING ON THE JAX HOMEPAGE TO COVER THIS DEVELOPING SITUATION.

&&

.AVIATION...MAIN THREAT TONIGHT WILL BE WIND SHEAR WHICH SHOULD
DEVELOP AFT 06Z. FOR THE MOST PART...LOOKS TO BE VFR INITIALLY FOR
THE FL TAF SITES THOUGH THU MORNING. SSI WILL SEE SOME MVFR
DEVELOP IN LIGHT RA DURING THE OVERNIGHT PERIOD...BUT MAIN EVENT
LOOKS TO HOLD OFF UNTIL 18Z. STILL LOOKS ON TRACK FOR A POTENTIAL
SQUALL LINE WITH STRONG WIND GUST POTENTIAL FOR ALL TAF SITES THU AFTERNOON.

&&

.MARINE...LIGHT WINDS CONTINUE AT THE BUOYS THIS EVENING WITH 10
KNOTS OR LESS WHICH MATCH CURRENT GRIDS QUITE WELL. THESE WINDS
WILL BE PICKING UP RAPIDLY ON THURSDAY AND CURRENT SCA LOOKS ON
TRACK. NO CHANGES ARE PLANNED.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  52  68  52  67 /  70  80  30   0
SSI  55  67  56  67 /  70  80  40   0
JAX  52  74  56  71 /  50  80  40  10
SGJ  56  76  61  71 /  40  60  50  10
GNV  51  75  57  71 /  40  70  50  10
OCF  53  77  59  72 /  30  60  60  20

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY FROM 10 AM THURSDAY TO 10 AM EST FRIDAY FOR
     FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-
     ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE.

     SMALL CRAFT ADVISORY FROM NOON THURSDAY TO 10 AM EST FRIDAY FOR
     ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM
     OFFSHORE.

&&

DEESE/CARROLL/PRESNALL

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE JACKSONVILLE FL
455 PM EST WED JAN 20 2010

FLZ020>025-030>033-035>038-040-GAZ132>136-149>154-162>166-211100-
ALACHUA-APPLING-ATKINSON-BACON-BAKER-BRADFORD-BRANTLEY-
CAMDEN (COASTAL)-CAMDEN (INLAND)-CHARLTON-CLAY-CLINCH-COFFEE-
COLUMBIA-DUVAL-ECHOLS-FLAGLER-GILCHRIST-GLYNN (COASTAL)-
GLYNN (INLAND)-HAMILTON-JEFF DAVIS-MARION-NASSAU-PIERCE-PUTNAM-
ST JOHNS-SUWANNEE-UNION-WARE-WAYNE-
455 PM EST WED JAN 20 2010

THIS OUTLOOK IS FOR NORTHEAST FLORIDA AND SOUTHEAST GEORGIA.

.DAY ONE...REST OF TODAY AND TONIGHT...

ISOLATED THUNDERSTORMS WILL BE POSSIBLE LATE TONIGHT...MAINLY ALONG
AN NORTH OF THE I-10 CORRIDOR...AS SEVERAL DISTURBANCES ADVANCE
ACROSS THE AREA. GUSTY WINDS AND LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE WITH ANY THUNDERSTORM DEVELOPMENT.

THE ALTAMAHA RIVER AT BAXLEY IS FORECAST TO REACH FLOOD STAGE
TODAY...WITH MINOR FLOODING EXPECTED INTO NEXT WEEK.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

...SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY...

THE INTERACTION OF INCREASING MOISTURE...DAYTIME HEATING AND AN
APPROACHING UPPER LEVEL DISTURBANCE WILL PROVIDE FAVORABLE
INGREDIENTS FOR STRONG TO POSSIBLY SEVERE THUNDERSTORMS ON
THURSDAY...ESPECIALLY FROM LATE MORNING TO EARLY EVENING. THE MAIN
CONCERNS WILL BE STRONG AND POSSIBLY DAMAGING WINDS...HEAVY RAINFALL
AND HAIL...ALTHOUGH INCREASING WIND SHEAR WILL ALSO PROMOTE ROTATING
THUNDERSTORMS WITH THE POTENTIAL FOR ISOLATED TORNADOES. INDIVIDUAL
THUNDERSTORMS ARE EXPECTED IN THE MORNING...WITH INCREASING ACTIVITY
IN THE AFTERNOON. IN ADDITION...THERE IS THE POTENTIAL FOR A SQUALL
LINE TO ADVANCE EAST ACROSS THE AREA IN THE AFTERNOON AND EARLY
EVENING. LAW ENFORCEMENT AGENCIES...EMERGENCY MANAGEMENT
OFFICIALS...STORM SPOTTER GROUPS...AND OTHER INTERESTED CONCERNS
SHOULD MONITOR THIS SITUATION AND TAKE APPROPRIATE ACTION SHOULD
POTENTIAL SEVERE WEATHER BECOME IMMINENT.

SCATTERED THUNDERSTORMS WILL BE POSSIBLE SUNDAY EVENING AS ANOTHER
COLD FRONT MOVES THROUGH THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUESTED ON THURSDAY.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE
IN JACKSONVILLE WEBSITE ON THE INTERNET AT WEATHER.GOV/JAX.

ECZ/SEC