Alert archive / Georgia / Tornado Watches in 2009

Tornado Watch 800

December 8, 200923 counties in Alabama; 25 counties in Georgia

The Storm Prediction Center issued this tornado watch at Dec 8, 2009, 11:09 PM CST for 23 counties in Alabama; 25 counties in Georgia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Dec 8, 2009, 11:09 PM CST (05:09 UTC)
Expired
Dec 9, 2009, 4:13 AM 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

Autauga County, AL, Bullock County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Cullman County, AL, DeKalb County, AL, Elmore County, AL, Etowah County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marshall County, AL, Montgomery County, AL, Randolph County, AL, Russell County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Bartow County, GA, Carroll County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dade County, GA, Douglas County, GA, Fayette County, GA, Floyd County, GA, Fulton County, GA, Gordon County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Meriwether County, GA, Murray County, GA, Muscogee County, GA, Paulding County, GA, Polk County, GA, Troup County, GA, Walker County, GA, Whitfield County, GA

The radar

The Birmingham radar (KBMX), 65 km from the middle of the area, began a volume at 05:10 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
30%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
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
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Dec 8, 11:14 PM CSTTornado WarningBMXBlount, Etowah, St. Clair22 min
Dec 8, 11:30 PM CSTFlash Flood WarningHUNCullman60 min
Dec 8, 11:46 PM CSTSevere Thunderstorm WarningFFCCatoosa, Dade, Walker29 min
Dec 9, 12:01 AM CSTSevere Thunderstorm WarningFFCChattooga, Floyd, Walker44 min
Dec 9, 12:09 AM CSTSevere Thunderstorm WarningBMXBlount, Jefferson, St. Clair51 min
Dec 9, 12:18 AM CSTSevere Thunderstorm WarningFFCGordon, Murray, Whitfield42 min
Dec 9, 12:23 AM CSTSevere Thunderstorm WarningBMXBibb, Chilton, Coosa, Hale, Marengo, Perry and 1 more52 min
Dec 9, 12:28 AM CSTFlash Flood WarningHUNCullman, DeKalb, Jackson, Madison, Marshall, Morgan2 hr
Dec 9, 12:31 AM CSTFlash Flood WarningFFCChattooga, Floyd, Walker6 hr
Dec 9, 1:05 AM CSTSevere Thunderstorm WarningBMXChilton, Clay, Coosa, Shelby, Talladega40 min
Dec 9, 1:11 AM CSTSevere Thunderstorm WarningBMXAutauga, Chilton, Coosa, Elmore49 min
Dec 9, 1:23 AM CSTSevere Thunderstorm WarningFFCFloyd, Polk32 min
Dec 9, 1:30 AM CSTFlash Flood WarningBMXClay, Talladega90 min
Dec 9, 1:37 AM CSTSevere Thunderstorm WarningBMXClay, Cleburne, Randolph38 min
Dec 9, 1:40 AM CSTFlash Flood WarningFFCGordon, Murray, Whitfield6 hr
Dec 9, 2:01 AM CSTSevere Thunderstorm WarningBMXChambers, Randolph, Tallapoosa44 min
Dec 9, 2:53 AM CSTSevere Thunderstorm WarningFFCCoweta, Fayette22 min
Dec 9, 3:03 AM CSTSevere Thunderstorm WarningFFCClayton, Henry, Newton, Rockdale, Spalding27 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

Birmingham, AL (KBMX), launched 00:00Z, 5.2 hours before the alert went out and 66 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, Birmingham, AL at 00:00Z on 2009-12-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 11 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, Birmingham, AL at 00:00Z on 2009-12-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 644 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
11 J/kg
Mixed-layer CIN
-328 J/kg
Mixed-layer LCL
495 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
644 m²/s²
0-3 km storm-relative helicity
840 m²/s²
Significant tornado parameter
0.0
Supercell composite
4.2

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 8, 6:12 PM CSTTornado WatchSPCBibb, Blount, Choctaw, Clarke, Dallas, Fayette and 15 more8 hr
Dec 8, 9:47 PM CSTMesoscale DiscussionSPCBibb, Blount, Choctaw, Clarke, Colbert, Cullman and 18 more88 min
Dec 8, 10:24 PM CSTMesoscale DiscussionSPCCalhoun, Chambers, Cherokee, Clay, Cleburne, Coosa and 10 more96 min
Dec 9, 2:20 AM CSTMesoscale DiscussionSPCBarbour, Bullock, Butler, Chambers, Coffee, Conecuh and 16 more85 min
Dec 9, 3:32 AM CSTTornado WatchSPCCoffee, Dale, Geneva, Henry, Houston5 hr
Dec 9, 5:11 AM CSTTornado WatchSPCBurke, Columbia, Richmond4 hr
Dec 9, 7:15 AM CSTMesoscale DiscussionSPCBaker, Ben Hill, Candler, Coffee, Colquitt, Decatur and 13 more60 min
Dec 9, 10:29 AM CSTMesoscale DiscussionSPCBrantley, Brooks, Charlton, Clinch, Echols, Lanier and 3 more91 min

Nearby

Tornado Watches in Georgia, 2009Tornado Watches in Alabama, 2009Every tornado watch in 2009

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.