Alert archive / Tennessee / Tornado Watches in 2021
Tornado Watch 31
The Storm Prediction Center issued this tornado watch at Mar 17, 2021, 12:59 PM CDT for 19 counties in Tennessee. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 17, 2021, 12:59 PM CDT (17:59 UTC)
- Expired
- Mar 17, 2021, 7:00 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 65 kt
Counties Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN
The radar
The Memphis radar (KNQA), 95 km from the middle of the area, began a volume at 18:00 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
- 50%
- One or more gusts of 65 knots or more
- 30%
- 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
- 70%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 17, 1:18 PM CDT | Severe Thunderstorm Warning | MEG | Chester, Fayette, Hardeman, Haywood, Madison, Tipton | 42 min |
| Mar 17, 1:54 PM CDT | Flash Flood Warning | MEG | Shelby | 3 hr |
| Mar 17, 1:58 PM CDT | Severe Thunderstorm Warning | MEG | Chester, Decatur, Hardeman, Henderson, Madison | 47 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
Little Rock, AR (KLZK), launched 12:00Z, 6.0 hours before the alert went out and 122 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
- 18 J/kg
- Mixed-layer CIN
- -262 J/kg
- Mixed-layer LCL
- 1466 m above ground
- 0-6 km bulk shear
- 65 kt
- 0-1 km storm-relative helicity
- 217 m²/s²
- 0-3 km storm-relative helicity
- 186 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted.
806
WWUS20 KWNS 171742
SEL1
SPC WW 171742
TNZ000-180000-
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 31
NWS Storm Prediction Center Norman OK
1245 PM CDT Wed Mar 17 2021
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Western Tennessee
* Effective this Wednesday afternoon and evening from 1245 PM
until 700 PM CDT.
* Primary threats include...
A couple tornadoes possible
Scattered damaging winds and isolated significant gusts to 75
mph possible
Isolated large hail events to 1 inch in diameter possible
SUMMARY...Generally linear clusters should persist east-northeast
across western Tennessee this afternoon. With a high shear, low CAPE
environment, a risk for damaging winds and a couple tornadoes may
develop.
The tornado watch area is approximately along and 45 statute miles
north and south of a line from 50 miles east of Jackson TN to 50
miles southwest of Dyersburg TN. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU1).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 26...WW 27...WW 28...WW
29...WW 30...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 24035.
...GramsSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 17, 5:34 AM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Bolivar, Calhoun, Coahoma, DeSoto and 15 more | 86 min |
| Mar 17, 5:53 AM CDT | Tornado Watch | SPC | Alcorn, Benton, Bolivar, Calhoun, Chickasaw, Coahoma and 20 more | 7 hr |
| Mar 17, 7:38 AM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Coahoma, DeSoto, Itawamba, Lafayette and 11 more | 67 min |
| Mar 17, 10:56 AM CDT | Mesoscale Discussion | SPC | Attala, Choctaw, Clarke, Clay, Copiah, Covington and 26 more | 2 hr |
| Mar 17, 11:36 AM CDT | Tornado Watch | SPC | Attala, Choctaw, Clarke, Clay, Copiah, Covington and 28 more | 7 hr |
| Mar 17, 12:02 PM CDT | Mesoscale Discussion | SPC | Clarke, Jones, Wayne | 58 min |
| Mar 17, 12:15 PM CDT | Mesoscale Discussion | SPC | Bolivar, Calhoun, Carroll, Claiborne, Coahoma, Grenada and 22 more | 90 min |
| Mar 17, 12:57 PM CDT | Tornado Watch | SPC | Adams, Alcorn, Benton, Bolivar, Calhoun, Carroll and 32 more | 6 hr |
| Mar 17, 1:19 PM CDT | Mesoscale Discussion | SPC | Jefferson Davis, Lawrence, Lincoln, Simpson, Smith | 86 min |
| Mar 17, 1:45 PM CDT | Mesoscale Discussion | SPC | Amite, Forrest, George, Greene, Hancock, Harrison and 9 more | 90 min |
| Mar 17, 2:38 PM CDT | Tornado Watch | SPC | Amite, Hancock, Harrison, Jackson, Pearl River, Pike and 2 more | 8 hr |
| Mar 17, 2:56 PM CDT | Mesoscale Discussion | SPC | Adams, Attala, Bolivar, Calhoun, Carroll, Chickasaw and 41 more | 94 min |
| Mar 17, 5:49 PM CDT | Mesoscale Discussion | SPC | Clarke, Covington, Forrest, George, Greene, Jasper and 13 more | 86 min |
| Mar 17, 6:09 PM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, Bolivar, Calhoun, Carroll, Chickasaw and 25 more | 66 min |
| Mar 17, 6:48 PM CDT | Tornado Watch | SPC | Attala, Choctaw, Clarke, Clay, Covington, Forrest and 20 more | 8 hr |
| Mar 17, 2:16 PM CDT | Mesoscale Discussion | SPC | Bedford, Benton, Cannon, Coffee, Davidson, Decatur and 18 more | 59 min |
Nearby
Tornado Watches in Tennessee, 2021Every tornado watch in 2021
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.