Alert archive / Alabama / Tornado Watches in 2020
Tornado Watch 109
The Storm Prediction Center issued this tornado watch at Apr 12, 2020, 3:20 PM CDT for 36 counties in Alabama; 6 counties in Tennessee. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 12, 2020, 3:20 PM CDT (20:20 UTC)
- Expired
- Apr 12, 2020, 11:38 PM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 70 kt
All 42 counties
Bibb County, AL, Blount County, AL, Calhoun County, AL, Cherokee County, AL, Chilton County, AL, Clay County, AL, Cleburne County, AL, Colbert County, AL, Coosa County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Hale County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marengo County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Perry County, AL, Pickens County, AL, Shelby County, AL, St. Clair County, AL, Sumter County, AL, Talladega County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, Franklin County, TN, Giles County, TN, Lawrence County, TN, Lincoln County, TN, Moore County, TN, Wayne County, TN
The radar
The Birmingham radar (KBMX), 110 km from the middle of the area, began a volume at 20:24 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
- 80%
- One or more EF2 to EF5 tornadoes
- 70%
- Ten or more severe wind reports
- 80%
- One or more gusts of 65 knots or more
- 60%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 95%
Warnings issued inside it
44 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 12, 3:26 PM CDT | Tornado Warning | BMX | Pickens | 64 min |
| Apr 12, 3:33 PM CDT | Severe Thunderstorm Warning | BMX | Lamar, Marion | 40 min |
| Apr 12, 3:35 PM CDT | Severe Thunderstorm Warning | HUN | Franklin | 55 min |
| Apr 12, 4:10 PM CDT | Tornado Warning | BMX | Fayette, Tuscaloosa | 50 min |
| Apr 12, 4:40 PM CDT | Tornado Warning | BMX | Walker | 49 min |
| Apr 12, 4:50 PM CDT | Severe Thunderstorm Warning | BMX | Jefferson | 55 min |
| Apr 12, 5:07 PM CDT | Tornado Warning | BMX | Jefferson | 53 min |
| Apr 12, 5:27 PM CDT | Severe Thunderstorm Warning | HUN | Cullman | 33 min |
| Apr 12, 5:28 PM CDT | Severe Thunderstorm Warning | BMX | Blount, St. Clair | 46 min |
| Apr 12, 5:31 PM CDT | Tornado Warning | BMX | Blount | 44 min |
| Apr 12, 5:50 PM CDT | Severe Thunderstorm Warning | BMX | Etowah | 55 min |
| Apr 12, 5:59 PM CDT | Tornado Warning | BMX | Etowah | 35 min |
| Apr 12, 6:19 PM CDT | Tornado Warning | BMX | Cherokee | 56 min |
| Apr 12, 6:24 PM CDT | Tornado Warning | HUN | DeKalb, Marshall | 36 min |
| Apr 12, 6:41 PM CDT | Flash Flood Warning | BMX | Blount | 6 hr |
| Apr 12, 6:52 PM CDT | Flash Flood Warning | HUN | DeKalb, Marshall | 3 hr |
| Apr 12, 7:10 PM CDT | Tornado Warning | BMX | Greene | 22 min |
| Apr 12, 7:14 PM CDT | Tornado Warning | BMX | Sumter | 26 min |
| Apr 12, 8:08 PM CDT | Severe Thunderstorm Warning | BMX | Fayette, Walker | 55 min |
| Apr 12, 8:15 PM CDT | Tornado Warning | BMX | Walker, Winston | 15 min |
| Apr 12, 8:21 PM CDT | Flash Flood Warning | HUN | Cullman | 8 hr |
| Apr 12, 8:22 PM CDT | Severe Thunderstorm Warning | HUN | Cullman, Marshall, Morgan | 53 min |
| Apr 12, 8:25 PM CDT | Severe Thunderstorm Warning | BMX | Tuscaloosa | 38 min |
| Apr 12, 8:29 PM CDT | Flash Flood Warning | BMX | Fayette, Greene, Jefferson, Pickens, Sumter, Tuscaloosa and 1 more | 5 hr |
| Apr 12, 8:32 PM CDT | Tornado Warning | BMX | Jefferson, Tuscaloosa | 21 min |
| Apr 12, 8:36 PM CDT | Severe Thunderstorm Warning | BMX | Blount, Jefferson | 54 min |
| Apr 12, 8:36 PM CDT | Tornado Warning | BMX | Jefferson, Tuscaloosa | 17 min |
| Apr 12, 8:40 PM CDT | Tornado Warning | HUN | Cullman, Morgan | 35 min |
| Apr 12, 8:51 PM CDT | Severe Thunderstorm Warning | BMX | Jefferson | 39 min |
| Apr 12, 9:12 PM CDT | Tornado Warning | BMX | Blount | 20 min |
| Apr 12, 9:12 PM CDT | Tornado Warning | HUN | Cullman, Madison, Marshall, Morgan | 33 min |
| Apr 12, 9:19 PM CDT | Severe Thunderstorm Warning | BMX | Blount, Etowah, Jefferson, St. Clair, Shelby | 71 min |
| Apr 12, 9:25 PM CDT | Flash Flood Warning | HUN | Cullman, DeKalb, Jackson, Madison, Marshall, Morgan | 7 hr |
| Apr 12, 9:33 PM CDT | Tornado Warning | BMX | Marengo | 27 min |
| Apr 12, 9:34 PM CDT | Tornado Warning | HUN | DeKalb, Marshall | 26 min |
| Apr 12, 9:54 PM CDT | Flash Flood Warning | HUN | DeKalb, Marshall | 6 hr |
| Apr 12, 9:55 PM CDT | Tornado Warning | HUN | DeKalb, Jackson | 5 min |
| Apr 12, 9:59 PM CDT | Severe Thunderstorm Warning | HUN | DeKalb, Jackson, Marshall | 31 min |
| Apr 12, 10:03 PM CDT | Flash Flood Warning | HUN | Marshall | 6 hr |
| Apr 12, 10:19 PM CDT | Tornado Warning | HUN | DeKalb | 26 min |
| Apr 12, 10:22 PM CDT | Flash Flood Warning | BMX | Blount, Calhoun, Cherokee, Etowah, St. Clair | 4 hr |
| Apr 12, 10:24 PM CDT | Tornado Warning | BMX | Cherokee | 36 min |
| Apr 12, 10:47 PM CDT | Severe Thunderstorm Warning | BMX | Calhoun, Cherokee, Cleburne, Etowah | 58 min |
| Apr 12, 10:59 PM CDT | Severe Thunderstorm Warning | BMX | Chilton, Clay, Coosa, Shelby, Talladega, Tallapoosa | 43 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, 8.3 hours before the alert went out and 109 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
- 1885 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 336 m²/s²
- 0-3 km storm-relative helicity
- 578 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 |
|---|---|---|---|---|
| Apr 12, 1:45 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Cherokee, Chilton and 33 more | 90 min |
| Apr 12, 3:38 PM CDT | Mesoscale Discussion | SPC | Fayette, Greene, Lamar, Pickens, Sumter, Tuscaloosa and 1 more | 97 min |
| Apr 12, 3:53 PM CDT | Mesoscale Discussion | SPC | Clarke, Washington | 97 min |
| Apr 12, 4:38 PM CDT | Tornado Watch | SPC | Autauga, Baldwin, Bibb, Calhoun, Chilton, Choctaw and 22 more | 7 hr |
| Apr 12, 4:54 PM CDT | Mesoscale Discussion | SPC | Choctaw | 66 min |
| Apr 12, 5:14 PM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Cleburne, Cullman, DeKalb and 13 more | 91 min |
| Apr 12, 5:44 PM CDT | Mesoscale Discussion | SPC | Lamar, Marion | 91 min |
Nearby
Tornado Watches in Alabama, 2020Tornado Watches in Tennessee, 2020Every tornado watch in 2020
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.