Alert archive / Tennessee / Mesoscale Discussions in 2018
Mesoscale Discussion 479
The Storm Prediction Center issued this mesoscale discussion at May 20, 2018, 6:26 PM CDT for 5 states. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- May 20, 2018, 6:26 PM CDT (23:26 UTC)
- Expired
- May 20, 2018, 7:30 PM CDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
All 77 counties
Arkansas County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Jackson County, AR, Lawrence County, AR, Lee County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, St. Francis County, AR, Woodruff County, AR, Caldwell County, KY, Calloway County, KY, Christian County, KY, Fulton County, KY, Graves County, KY, Henderson County, KY, Hickman County, KY, Hopkins County, KY, Lyon County, KY, Marshall County, KY, McLean County, KY, Trigg County, KY, Webster County, KY, Dunklin County, MO, Pemiscot County, MO, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Chickasaw County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Itawamba County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Monroe County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Yalobusha 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), 66 km from the middle of the area, began a volume at 23:28 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
Little Rock, AR (KBYH), launched 12:00Z, 11.4 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
- 1368 J/kg
- Mixed-layer CIN
- -61 J/kg
- Mixed-layer LCL
- 1256 m above ground
- 0-6 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- -28 m²/s²
- 0-3 km storm-relative helicity
- -10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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, 1:11 AM CDT | Mesoscale Discussion | SPC | Polk, Scott, Sebastian | 2 hr |
| May 20, 11:43 AM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Independence and 11 more | 3 hr |
| May 20, 12:32 PM CDT | Severe Thunderstorm Watch | SPC | Clay, Craighead, Crittenden, Cross, Greene, Lawrence and 6 more | 6 hr |
| May 20, 3:32 PM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more | 118 min |
| May 20, 3:32 PM CDT | Severe Thunderstorm Watch | SPC | Benton | 4 hr |
| May 20, 6:25 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll | 95 min |
| May 20, 5:40 PM CDT | Mesoscale Discussion | SPC | Boone, Boyd, Bracken, Campbell, Carter, Fleming and 11 more | 3 hr |
| May 19, 7:41 PM CDT | Mesoscale Discussion | SPC | Bates, Benton, Cass, Henry, Johnson, Pettis | 94 min |
| May 20, 12:42 AM CDT | Mesoscale Discussion | SPC | Barton, Bates, Benton, Camden, Cass, Cedar and 28 more | 3 hr |
| May 20, 2:24 PM CDT | Mesoscale Discussion | SPC | Barry, Barton, Bates, Benton, Camden, Cedar and 16 more | 3 hr |
Nearby
Mesoscale Discussions in Tennessee, 2018Mesoscale Discussions in Mississippi, 2018Mesoscale Discussions in Arkansas, 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.