Alert archive / Tennessee / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 31
The Storm Prediction Center issued this severe thunderstorm watch at Feb 8, 2017, 4:53 PM CST for 4 states. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 8, 2017, 4:53 PM CST (22:53 UTC)
- Expired
- Feb 8, 2017, 10:44 PM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 83 counties
Blount County, AL, Cherokee 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, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Fannin County, GA, Floyd County, GA, Gilmer County, GA, Gordon County, GA, Murray County, GA, Pickens County, GA, Polk County, GA, Walker County, GA, Whitfield County, GA, Cherokee County, NC, Anderson County, TN, Bedford County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Campbell County, TN, Cannon County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, DeKalb County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Jackson County, TN, Knox County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Loudon County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Moore County, TN, Morgan County, TN, Overton County, TN, Polk County, TN, Putnam County, TN, Rhea County, TN, Roane County, TN, Rutherford County, TN, Scott County, TN, Sequatchie County, TN, Smith County, TN, Trousdale County, TN, Union County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Williamson County, TN, Wilson County, TN
The radar
The Northeast Alabama radar (KHTX), 55 km from the middle of the area, began a volume at 22:56 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
- 10%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 10%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 8, 5:27 PM CST | Severe Thunderstorm Warning | MRX | Campbell, Claiborne, Union | 47 min |
| Feb 8, 6:12 PM CST | Severe Thunderstorm Warning | HUN | Lawrence | 33 min |
| Feb 8, 6:15 PM CST | Severe Thunderstorm Warning | BMX | Lamar, Marion | 30 min |
| Feb 8, 6:29 PM CST | Severe Thunderstorm Warning | HUN | Lawrence, Limestone | 31 min |
| Feb 8, 6:43 PM CST | Severe Thunderstorm Warning | HUN | Lawrence, Limestone, Madison, Morgan | 47 min |
| Feb 8, 7:06 PM CST | Severe Thunderstorm Warning | HUN | Cullman, Lawrence, Morgan | 24 min |
| Feb 8, 9:24 PM CST | Severe Thunderstorm Warning | FFC | Bartow, Floyd | 36 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, 10.9 hours before the alert went out and 95 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
- 2 J/kg
- Mixed-layer CIN
- -175 J/kg
- Mixed-layer LCL
- 573 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 74 m²/s²
- 0-3 km storm-relative helicity
- 144 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 |
|---|---|---|---|---|
| Feb 8, 3:02 PM CST | Mesoscale Discussion | SPC | Colbert, Cullman, DeKalb, Franklin, Jackson, Lauderdale and 7 more | 118 min |
| Feb 7, 6:37 PM CST | Severe Thunderstorm Watch | SPC | Appling, Atkinson, Bacon, Brantley, Charlton, Clinch and 6 more | 3 hr |
| Feb 7, 8:36 PM CST | Mesoscale Discussion | SPC | Brantley, Camden, Charlton | 114 min |
| Feb 8, 2:45 PM CST | Mesoscale Discussion | SPC | Atkinson, Berrien, Brantley, Brooks, Camden, Charlton and 11 more | 60 min |
Nearby
Severe Thunderstorm Watches in Tennessee, 2017Severe Thunderstorm Watches in Alabama, 2017Severe Thunderstorm Watches in Georgia, 2017Every severe thunderstorm watch in 2017
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.