Alert archive / Georgia / Tornado Watches in 2007

Tornado Watch 738

December 15, 20075 counties in Alabama; 17 counties in Florida; 26 counties in Georgia

The Storm Prediction Center issued this tornado watch at Dec 15, 2007, 3:47 PM CST for 5 counties in Alabama; 17 counties in Florida; 26 counties in Georgia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Dec 15, 2007, 3:47 PM CST (21:47 UTC)
Expired
Dec 15, 2007, 8:48 PM CST
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 48 counties

Coffee County, AL, Dale County, AL, Geneva County, AL, Henry County, AL, Houston County, AL, Bay County, FL, Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Clay County, GA, Colquitt County, GA, Cook County, GA, Decatur County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Irwin County, GA, Lanier County, GA, Lee County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Quitman County, GA, Randolph County, GA, Seminole County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Worth County, GA

The radar

The Tallahassee radar (KTLH), 80 km from the middle of the area, began a volume at 21:50 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
20%
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
10%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Dec 15, 4:37 PM CSTTornado WarningTAEWalton23 min
Dec 15, 4:38 PM CSTTornado WarningTAEEarly29 min
Dec 15, 4:48 PM CSTSevere Thunderstorm WarningTAEBay57 min
Dec 15, 4:59 PM CSTTornado WarningTAEWalton, Washington46 min
Dec 15, 6:31 PM CSTSevere Thunderstorm WarningTAEEarly, Miller29 min
Dec 15, 6:58 PM CSTSevere Thunderstorm WarningTAEBaker, Calhoun, Dougherty, Early32 min
Dec 15, 8:01 PM CSTSevere Thunderstorm WarningTAETurner, Worth29 min
Dec 15, 8:06 PM CSTTornado WarningTAETurner, Worth23 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 9.8 hours before the alert went out and 82 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, Tallahassee Rgnl, FL at 12:00Z on 2007-12-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 39 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, Tallahassee Rgnl, FL at 12:00Z on 2007-12-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 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
39 J/kg
Mixed-layer CIN
-96 J/kg
Mixed-layer LCL
636 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

320 
WWUS20 KWNS 152144
SEL8  
SPC WW 152144
ALZ000-FLZ000-GAZ000-CWZ000-160400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 738
NWS STORM PREDICTION CENTER NORMAN OK
445 PM EST SAT DEC 15 2007

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

       SOUTHEAST ALABAMA
       FLORIDA PANHANDLE
       SOUTHWEST GEORGIA
       COASTAL WATERS

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 445 PM UNTIL
1100 PM EST.

TORNADOES...HAIL TO 0.5 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 75 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 40 MILES WEST NORTHWEST OF
PANAMA CITY FLORIDA TO 15 MILES EAST NORTHEAST OF VALDOSTA
GEORGIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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...THUNDERSTORMS CONTINUE TO INCREASE IN COVERAGE AND
INTENSITY OVER SOUTHEAST AL/FL PANHANDLE/SOUTHWEST GA AHEAD OF
DEEPENING SURFACE LOW.  STRONG LOW LEVEL VERTICAL SHEAR AND
DEWPOINTS IN THE 70S WILL PROMOTE A RISK OF SUPERCELL STORM
STRUCTURES CAPABLE OF DAMAGING WINDS AND ISOLATED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 24035.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 15, 12:47 PM CSTMesoscale DiscussionSPCBaldwin, Barbour, Coffee, Conecuh, Covington, Crenshaw and 6 more88 min
Dec 15, 5:31 PM CSTMesoscale DiscussionSPCCoffee, Dale, Geneva, Henry, Houston119 min

Nearby

Tornado Watches in Georgia, 2007Tornado Watches in Florida, 2007Tornado Watches in Alabama, 2007Every tornado watch in 2007

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.