Alert archive / Alabama / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 576
The Storm Prediction Center issued this severe thunderstorm watch at Aug 13, 2012, 12:38 PM CDT for 4 states. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 13, 2012, 12:38 PM CDT (17:38 UTC)
- Expired
- Aug 13, 2012, 4:42 PM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 45 counties
Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Cullman County, AL, Dallas County, AL, DeKalb County, AL, Etowah County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marengo County, AL, Marshall County, AL, Morgan County, AL, Perry County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Washington County, AL, Wilcox County, AL, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Floyd County, GA, Walker County, GA, Wayne County, MS, Bledsoe County, TN, Coffee County, TN, Franklin County, TN, Grundy County, TN, Hamilton County, TN, Lincoln County, TN, Marion County, TN, Moore County, TN, Rhea County, TN, Sequatchie County, TN, Van Buren County, TN, Warren County, TN
The radar
The Birmingham radar (KBMX), 84 km from the middle of the area, began a volume at 17:39 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
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 12:43 PM CDT | Severe Thunderstorm Warning | HUN | Lawrence, Limestone, Madison, Morgan | 32 min |
| Aug 13, 12:47 PM CDT | Severe Thunderstorm Warning | HUN | Lincoln | 28 min |
| Aug 13, 1:12 PM CDT | Severe Thunderstorm Warning | HUN | Limestone, Madison, Morgan | 33 min |
| Aug 13, 1:43 PM CDT | Severe Thunderstorm Warning | HUN | Jackson, Madison, Marshall, Morgan | 21 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 12:00Z, 5.6 hours before the alert went out and 83 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1302 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 100 m²/s²
- 0-3 km storm-relative helicity
- 115 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 13, 12:21 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 22 more | 24 min |
| Aug 13, 3:49 PM CDT | Mesoscale Discussion | SPC | Cleburne | 56 min |
| Aug 13, 7:48 AM CDT | Mesoscale Discussion | SPC | Attala, Bolivar, Calhoun, Carroll, Choctaw, Clay and 20 more | 87 min |
| Aug 13, 3:15 PM CDT | Mesoscale Discussion | SPC | Benton, Bolivar, Carroll, Coahoma, DeSoto, Grenada and 12 more | 30 min |
| Aug 13, 3:32 PM CDT | Severe Thunderstorm Watch | SPC | Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 26 more | 7 hr |
| Aug 13, 5:14 PM CDT | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 20 more | 91 min |
Nearby
Severe Thunderstorm Watches in Alabama, 2012Severe Thunderstorm Watches in Tennessee, 2012Severe Thunderstorm Watches in Georgia, 2012Every severe thunderstorm watch in 2012
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.