Alert archive / Tennessee / Tornado Watches in 2008

Tornado Watch 198

April 11, 200819 counties in Alabama; 11 counties in Georgia; 31 counties in Tennessee

The Storm Prediction Center issued this tornado watch at Apr 11, 2008, 3:00 PM CDT for 19 counties in Alabama; 11 counties in Georgia; 31 counties in Tennessee. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 11, 2008, 3:00 PM CDT (20:00 UTC)
Expired
Apr 11, 2008, 8:26 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 61 counties

Blount County, AL, Calhoun County, AL, Cherokee County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Jackson County, AL, Jefferson County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Floyd County, GA, Gordon County, GA, Haralson County, GA, Murray County, GA, Polk County, GA, Walker County, GA, Whitfield County, GA, Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Campbell County, TN, Claiborne County, TN, Cumberland County, TN, Fentress County, TN, Franklin County, TN, Grainger County, TN, Grundy County, TN, Hamilton County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Morgan County, TN, Overton County, TN, Pickett County, TN, Polk County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, White County, TN

The radar

The Northeast Alabama radar (KHTX), 59 km from the middle of the area, began a volume at 20:01 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
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 11, 3:02 PM CDTTornado WarningMRXMorgan, Roane58 min
Apr 11, 3:04 PM CDTSevere Thunderstorm WarningMRXBledsoe56 min
Apr 11, 3:05 PM CDTTornado WarningBMXFayette, Pickens, Tuscaloosa25 min
Apr 11, 3:13 PM CDTTornado WarningHUNCullman32 min
Apr 11, 3:13 PM CDTTornado WarningOHXCumberland21 min
Apr 11, 3:14 PM CDTSevere Thunderstorm WarningHUNDeKalb29 min
Apr 11, 3:17 PM CDTSevere Thunderstorm WarningFFCDade, Walker39 min
Apr 11, 3:19 PM CDTSevere Thunderstorm WarningMRXSequatchie41 min
Apr 11, 3:23 PM CDTSevere Thunderstorm WarningHUNJackson52 min
Apr 11, 3:24 PM CDTSevere Thunderstorm WarningBMXGreene, Pickens, Sumter, Tuscaloosa51 min
Apr 11, 3:30 PM CDTSevere Thunderstorm WarningBMXFayette, Jefferson, Tuscaloosa, Walker45 min
Apr 11, 3:39 PM CDTSevere Thunderstorm WarningMRXMeigs, Rhea36 min
Apr 11, 3:41 PM CDTSevere Thunderstorm WarningBMXBlount, Walker19 min
Apr 11, 3:44 PM CDTSevere Thunderstorm WarningBMXBibb, Chilton, Jefferson, Perry, Shelby61 min
Apr 11, 3:46 PM CDTSevere Thunderstorm WarningMRXHamilton29 min
Apr 11, 3:46 PM CDTTornado WarningMRXAnderson, Campbell, Scott44 min
Apr 11, 3:50 PM CDTTornado WarningBMXJefferson, Tuscaloosa, Walker40 min
Apr 11, 3:52 PM CDTSevere Thunderstorm WarningBMXCalhoun, Cherokee, Etowah, St. Clair38 min
Apr 11, 3:55 PM CDTSevere Thunderstorm WarningMRXLoudon, Roane50 min
Apr 11, 4:01 PM CDTTornado WarningBMXCalhoun, Cherokee, Etowah, St. Clair44 min
Apr 11, 4:07 PM CDTSevere Thunderstorm WarningBMXBlount, Etowah38 min
Apr 11, 4:18 PM CDTTornado WarningBMXBlount, Jefferson, St. Clair42 min
Apr 11, 4:20 PM CDTSevere Thunderstorm WarningMRXCampbell, Claiborne, Grainger, Union40 min
Apr 11, 4:22 PM CDTSevere Thunderstorm WarningBMXBibb, Greene, Hale, Perry, Sumter, Tuscaloosa53 min
Apr 11, 4:24 PM CDTSevere Thunderstorm WarningFFCCatoosa, Murray, Whitfield36 min
Apr 11, 4:34 PM CDTSevere Thunderstorm WarningBMXJefferson, St. Clair, Shelby, Talladega41 min
Apr 11, 4:37 PM CDTSevere Thunderstorm WarningBMXJefferson, Tuscaloosa, Walker23 min
Apr 11, 4:42 PM CDTSevere Thunderstorm WarningBMXBibb, Chilton, Hale, Jefferson, Perry, Shelby and 1 more48 min
Apr 11, 4:42 PM CDTTornado WarningBMXCalhoun, Cherokee, Etowah33 min
Apr 11, 4:42 PM CDTSevere Thunderstorm WarningMRXBradley, Polk63 min
Apr 11, 4:53 PM CDTSevere Thunderstorm WarningFFCFloyd, Polk52 min
Apr 11, 4:56 PM CDTTornado WarningBMXBlount, Calhoun, Etowah, St. Clair24 min
Apr 11, 5:27 PM CDTSevere Thunderstorm WarningBMXBibb, Hale, Perry, Tuscaloosa48 min
Apr 11, 6:46 PM CDTTornado WarningBMXClay, Talladega29 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

Nashville Metro, TN (KBNA), launched 12:00Z, 8.0 hours before the alert went out and 140 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, Nashville Metro, TN at 12:00Z on 2008-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Nashville Metro, TN at 12:00Z on 2008-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -39 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
756 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
-39 m²/s²
0-3 km storm-relative helicity
119 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 2:15 AM CDTMesoscale DiscussionSPCLauderdale2 hr
Apr 11, 10:15 AM CDTTornado WatchSPCColbert, Cullman, DeKalb, Fayette, Franklin, Greene and 15 more5 hr
Apr 11, 1:15 PM CDTMesoscale DiscussionSPCAutauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 33 more2 hr
Apr 11, 3:07 PM CDTSevere Thunderstorm WatchSPCAutauga, Bibb, Butler, Chambers, Chilton, Choctaw and 18 more8 hr
Apr 11, 5:34 PM CDTMesoscale DiscussionSPCBibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 16 more56 min
Apr 10, 7:48 PM CDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Decatur and 21 more57 min
Apr 10, 8:22 PM CDTSevere Thunderstorm WatchSPCCarroll, Chester, Crockett, Decatur, Dyer, Fayette and 14 more5 hr
Apr 10, 9:54 PM CDTMesoscale DiscussionSPCBenton, Carroll, Chester, Crockett, Decatur, Dickson and 15 more66 min
Apr 10, 11:34 PM CDTMesoscale DiscussionSPCBenton, Carroll, Chester, Crockett, Decatur, Dyer and 17 more56 min

Nearby

Tornado Watches in Tennessee, 2008Tornado Watches in Alabama, 2008Tornado Watches in Georgia, 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.