Alert archive / Tennessee / Mesoscale Discussions in 2021
Mesoscale Discussion 208
The Storm Prediction Center issued this mesoscale discussion at Mar 17, 2021, 2:16 PM CDT for 24 counties in Tennessee. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- Mar 17, 2021, 2:16 PM CDT (19:16 UTC)
- Expired
- Mar 17, 2021, 3:15 PM CDT
- In force
- 59 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 24 counties
Bedford County, TN, Benton County, TN, Cannon County, TN, Coffee County, TN, Davidson County, TN, Decatur County, TN, Dickson County, TN, Franklin County, TN, Giles County, TN, Hardin County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Marshall County, TN, Maury County, TN, Moore County, TN, Perry County, TN, Rutherford County, TN, Warren County, TN, Wayne County, TN, Williamson County, TN
The radar
The Nashville radar (KOHX), 89 km from the middle of the area, began a volume at 19:20 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 nearest sounding before it
Nashville Metro, TN (KBNA), launched 12:00Z, 7.3 hours before the alert went out and 77 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
- 92 J/kg
- Mixed-layer CIN
- -304 J/kg
- Mixed-layer LCL
- 781 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 6 m²/s²
- 0-3 km storm-relative helicity
- 71 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
946
ACUS11 KWNS 171916
SWOMCD
SPC MCD 171916
TNZ000-ALZ000-172015-
Mesoscale Discussion 0208
NWS Storm Prediction Center Norman OK
0216 PM CDT Wed Mar 17 2021
Areas affected...Portions of Middle Tennessee
Concerning...Severe potential...Watch unlikely
Valid 171916Z - 172015Z
Probability of Watch Issuance...20 percent
SUMMARY...No watch is anticipated downstream of tornado watch 31.
DISCUSSION...A bowing segment has moved across western Tennessee
over the last hour and has recently had a weakening trend. No
observed strong/damaging winds have been reported from this line at
this time. Therefore, given the weakening trends with this activity,
its location to the north of the better surface based instability,
and lack of reports, do not plan to issue a watch across Middle
Tennessee at this time.
..Bentley.. 03/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OHX...HUN...MEG...
LAT...LON 36168833 36338773 36198658 35708564 35178591 34928602
34958775 35058839 36168833SPC 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 | Fayette, Hardeman, Haywood, McNairy, Shelby, Tipton | 86 min |
| Mar 17, 5:53 AM CDT | Tornado Watch | SPC | Fayette, Hardeman, Hardin, McNairy, Shelby | 7 hr |
| Mar 17, 7:38 AM CDT | Mesoscale Discussion | SPC | Fayette, Hardeman, McNairy, Shelby | 67 min |
| Mar 17, 12:59 PM CDT | Tornado Watch | SPC | Benton, Carroll, Chester, Crockett, Decatur, Dyer and 13 more | 6 hr |
| Mar 17, 6:09 PM CDT | Mesoscale Discussion | SPC | Chester, Fayette, Hardeman, Hardin, Haywood, Lawrence and 5 more | 66 min |
Nearby
Mesoscale Discussions in Tennessee, 2021Every mesoscale discussion 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.