Alert archive / Georgia / Tornado Watches in 2008

Tornado Watch 950

December 11, 200837 counties in Florida; 41 counties in Georgia

The Storm Prediction Center issued this tornado watch at Dec 11, 2008, 5:48 AM EST for 37 counties in Florida; 41 counties in Georgia. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Dec 11, 2008, 5:48 AM EST (10:48 UTC)
Expired
Dec 11, 2008, 12:00 PM EST
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 78 counties

Alachua County, FL, Baker County, FL, Bradford County, FL, Citrus County, FL, Clay County, FL, Columbia County, FL, Dixie County, FL, Duval County, FL, Flagler County, FL, Gilchrist County, FL, Hamilton County, FL, Hernando County, FL, Hillsborough County, FL, Jefferson County, FL, Lafayette County, FL, Lake County, FL, Leon County, FL, Levy County, FL, Madison County, FL, Manatee County, FL, Marion County, FL, Nassau County, FL, Orange County, FL, Osceola County, FL, Pasco County, FL, Pinellas County, FL, Polk County, FL, Putnam County, FL, Saint Johns County, FL, Sarasota County, FL, Seminole County, FL, Sumter County, FL, Suwannee County, FL, Taylor County, FL, Union County, FL, Volusia County, FL, Wakulla County, FL, Appling County, GA, Atkinson County, GA, Bacon County, GA, Ben Hill County, GA, Berrien County, GA, Brantley County, GA, Brooks County, GA, Bryan County, GA, Bulloch County, GA, Camden County, GA, Candler County, GA, Charlton County, GA, Chatham County, GA, Clinch County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Echols County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Glynn County, GA, Irwin County, GA, Jeff Davis County, GA, Jenkins County, GA, Lanier County, GA, Liberty County, GA, Long County, GA, Lowndes County, GA, McIntosh County, GA, Montgomery County, GA, Pierce County, GA, Screven County, GA, Tattnall County, GA, Telfair County, GA, Thomas County, GA, Toombs County, GA, Treutlen County, GA, Ware County, GA, Wayne County, GA, Wheeler County, GA

The radar

The Jacksonville radar (KJAX), 120 km from the middle of the area, began a volume at 10:50 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
10%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Dec 11, 6:10 AM ESTSevere Thunderstorm WarningTAEJefferson, Taylor, Wakulla35 min
Dec 11, 9:15 AM ESTSevere Thunderstorm WarningJAXAtkinson, Bacon, Coffee, Jeff Davis45 min
Dec 11, 9:40 AM ESTSevere Thunderstorm WarningJAXJeff Davis34 min
Dec 11, 9:48 AM ESTSevere Thunderstorm WarningJAXAppling, Bacon, Brantley, Charlton, Pierce, Ware and 1 more42 min
Dec 11, 10:23 AM ESTSevere Thunderstorm WarningJAXNassau52 min
Dec 11, 10:32 AM ESTSevere Thunderstorm WarningCHSCandler, Evans, Liberty, Long, McIntosh, Tattnall43 min
Dec 11, 10:36 AM ESTSevere Thunderstorm WarningFFCClarke, Emanuel, Glascock, Greene, Hancock, Jackson and 10 more39 min
Dec 11, 10:36 AM ESTTornado WarningJAXWayne10 min
Dec 11, 10:57 AM ESTSevere Thunderstorm WarningCHSBryan, Bulloch, Candler, Evans, Jenkins, Liberty and 1 more48 min
Dec 11, 11:28 AM ESTSevere Thunderstorm WarningCHSBryan, Bulloch, Chatham, Effingham, Liberty, Screven62 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Jacksonville, FL (KJAX), launched 00:00Z, 10.8 hours before the alert went out and 122 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Jacksonville, FL at 00:00Z on 2008-12-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 346 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jacksonville, FL at 00:00Z on 2008-12-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 117 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
346 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
963 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
117 m²/s²
0-3 km storm-relative helicity
104 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

295 
WWUS20 KWNS 111048
SEL0  
SPC WW 111048
FLZ000-GAZ000-CWZ000-111700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 950
NWS STORM PREDICTION CENTER NORMAN OK
550 AM EST THU DEC 11 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       A LARGE PART OF NORTHERN FLORIDA
       PARTS OF SOUTHERN AND SOUTHEASTERN GEORGIA
       COASTAL WATERS

EFFECTIVE THIS THURSDAY MORNING FROM 550 AM UNTIL NOON EST.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES WEST SOUTHWEST OF
AVON PARK FLORIDA TO 40 MILES NORTH NORTHWEST OF VIDALIA GEORGIA.
 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...STRONG SQUALL LINE OVER NERN GULF OF MEXICO DRIVEN BY
DEEPENING LOW SURFACE AND ALOFT WILL SWEEP E AND NE ACROSS THE WATCH
AREA THIS MORNING.  IN ADDITION TO STRONG/DAMAGING WINDS ASSOCIATED
WITH THE SQUALL LINE...EMBEDDED SUPERCELLS AND POSSIBLE TORNADOES
ARE ALSO A THREAT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450.
MEAN STORM MOTION VECTOR 22035.


...HALES

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 11, 5:27 AM ESTMesoscale DiscussionSPCAlachua, Baker, Bradford, Citrus, Clay, Columbia and 29 more33 min
Dec 11, 8:24 AM ESTMesoscale DiscussionSPCAlachua, Baker, Bradford, Brevard, Citrus, Clay and 20 more66 min
Dec 11, 11:21 AM ESTMesoscale DiscussionSPCOrange, Seminole, Volusia54 min
Dec 11, 10:01 AM ESTMesoscale DiscussionSPCBanks, Burke, Clarke, Columbia, Elbert, Franklin and 16 more119 min
Dec 11, 10:15 AM ESTSevere Thunderstorm WatchSPCBanks, Barrow, Burke, Clarke, Columbia, Elbert and 18 more4 hr

Nearby

Tornado Watches in Georgia, 2008Tornado Watches in Florida, 2008Every tornado watch in 2008

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.