Alert archive / Tennessee / Mesoscale Discussions in 2018
Mesoscale Discussion 809
The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2018, 12:31 PM CDT for 6 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jun 21, 2018, 12:31 PM CDT (17:31 UTC)
- Expired
- Jun 21, 2018, 3:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 79 counties
Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Lee County, AR, Mississippi County, AR, Poinsett County, AR, St. Francis County, AR, Alexander County, IL, Franklin County, IL, Gallatin County, IL, Hardin County, IL, Jackson County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Saline County, IL, Union County, IL, Williamson County, IL, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, Trigg County, KY, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Scott County, MO, Stoddard County, MO, Alcorn County, MS, Benton County, MS, DeSoto County, MS, Lafayette County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tate County, MS, Tippah County, MS, Tunica County, MS, Union County, MS, 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, Houston County, TN, Humphreys County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Perry County, TN, Shelby County, TN, Stewart County, TN, Tipton County, TN, Weakley County, TN
The radar
The Memphis radar (KNQA), 98 km from the middle of the area, began a volume at 17:32 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
Little Rock, AR (KBYH), launched 12:00Z, 5.5 hours before the alert went out and 153 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
- 399 J/kg
- Mixed-layer CIN
- -64 J/kg
- Mixed-layer LCL
- 736 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 79 m²/s²
- 0-3 km storm-relative helicity
- 64 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.8
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 |
|---|---|---|---|---|
| Jun 21, 1:39 PM CDT | Severe Thunderstorm Watch | SPC | Clay, Craighead, Crittenden, Cross, Greene, Lawrence and 5 more | 7 hr |
| Jun 21, 3:56 PM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Lee and 3 more | 2 hr |
| Jun 21, 1:53 PM CDT | Mesoscale Discussion | SPC | Henry, Knox, Marshall, Peoria, Rock Island, Stark and 2 more | 3 hr |
| Jun 21, 5:44 PM CDT | Mesoscale Discussion | SPC | Massac | 2 hr |
Nearby
Mesoscale Discussions in Tennessee, 2018Mesoscale Discussions in Kentucky, 2018Mesoscale Discussions in Mississippi, 2018Every mesoscale discussion in 2018
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.