Alert archive / Tennessee / Mesoscale Discussions in 2025
Mesoscale Discussion 906
The Storm Prediction Center issued this mesoscale discussion at May 20, 2025, 1:48 PM CDT for 20 counties in Alabama; 11 counties in Kentucky; 33 counties in Tennessee. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- May 20, 2025, 1:48 PM CDT (18:48 UTC)
- Expired
- May 20, 2025, 3:45 PM CDT
- In force
- 117 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 64 counties
Blount County, AL, Colbert County, AL, Cullman County, AL, DeKalb County, AL, Etowah County, AL, Fayette County, AL, Franklin County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, St. Clair County, AL, Walker County, AL, Winston County, AL, Allen County, KY, Barren County, KY, Butler County, KY, Christian County, KY, Edmonson County, KY, Logan County, KY, Muhlenberg County, KY, Simpson County, KY, Todd County, KY, Trigg County, KY, Warren County, KY, Bedford County, TN, Cannon County, TN, Cheatham County, TN, Coffee County, TN, Davidson County, TN, DeKalb County, TN, Dickson County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Macon County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Moore County, TN, Perry County, TN, Robertson County, TN, Rutherford County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Warren County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN
The radar
The Northeast Alabama radar (KHTX), 94 km from the middle of the area, began a volume at 18:49 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.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Nashville Metro, TN (KBNA), launched 12:00Z, 6.8 hours before the alert went out and 113 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
- 1162 J/kg
- Mixed-layer CIN
- -41 J/kg
- Mixed-layer LCL
- 904 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 114 m²/s²
- 0-3 km storm-relative helicity
- 137 m²/s²
- Significant tornado parameter
- 0.9
- Supercell composite
- 3.9
The text
As transmitted.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 10:19 AM CDT | Mesoscale Discussion | SPC | Colbert, Lauderdale, Limestone, Madison | 2 hr |
| May 20, 2:36 PM CDT | Tornado Watch | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 5 more | 8 hr |
| May 20, 3:33 PM CDT | Mesoscale Discussion | SPC | Colbert, Lauderdale | 117 min |
| May 20, 5:08 PM CDT | Mesoscale Discussion | SPC | Autauga, Bibb, Blount, Calhoun, Chilton, Clay and 20 more | 2 hr |
| May 20, 5:47 PM CDT | Mesoscale Discussion | SPC | Colbert, Lauderdale, Lawrence, Limestone, Madison | 118 min |
| May 20, 6:46 PM CDT | Tornado Watch | SPC | Bibb, Blount, Calhoun, Cherokee, Clay, Cleburne and 16 more | 7 hr |
| May 19, 7:02 PM CDT | Mesoscale Discussion | SPC | Logan, Simpson, Todd | 88 min |
| May 20, 1:07 AM CDT | Mesoscale Discussion | SPC | Ballard, Caldwell, Carlisle, Christian, Crittenden, Daviess and 16 more | 83 min |
| May 20, 2:15 AM CDT | Tornado Watch | SPC | Ballard, Caldwell, Carlisle, Crittenden, Daviess, Hancock and 11 more | 4 hr |
| May 20, 12:10 PM CDT | Tornado Watch | SPC | Bath, Bell, Bourbon, Boyd, Breathitt, Carter and 39 more | 5 hr |
| May 20, 1:09 PM CDT | Tornado Watch | SPC | Ballard, Calloway, Carlisle, Fulton, Graves, Hickman and 3 more | 8 hr |
| May 20, 2:42 PM CDT | Mesoscale Discussion | SPC | Floyd, Harlan, Johnson, Knott, Lawrence, Letcher and 3 more | 2 hr |
| May 20, 5:13 PM CDT | Mesoscale Discussion | SPC | Bell, Boyle, Breathitt, Clark, Clay, Estill and 25 more | 62 min |
| May 20, 6:27 PM CDT | Tornado Watch | SPC | Bell, Breathitt, Clay, Estill, Harlan, Jackson and 15 more | 6 hr |
| May 20, 12:34 PM CDT | Mesoscale Discussion | SPC | Crockett, Dyer, Fayette, Haywood, Lake, Lauderdale and 2 more | 116 min |
Nearby
Mesoscale Discussions in Tennessee, 2025Mesoscale Discussions in Alabama, 2025Mesoscale Discussions in Kentucky, 2025Every mesoscale discussion in 2025
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.