Alert archive / Tennessee / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 196

June 21, 20186 states

The Storm Prediction Center issued this severe thunderstorm watch at Jun 21, 2018, 1:39 PM CDT for 6 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jun 21, 2018, 1:39 PM CDT (18:39 UTC)
Expired: Jun 21, 2018, 9:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 79 counties

Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Lawrence County, AR, Lee County, AR, Mississippi County, AR, Poinsett County, AR, Randolph County, AR, St. Francis County, AR, Alexander County, IL, Hardin County, IL, Johnson County, IL, Massac County, IL, Pope County, IL, Pulaski County, IL, Union County, IL, Ballard County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Crittenden County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Hopkins County, KY, Livingston County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McLean County, KY, Muhlenberg County, KY, Todd County, KY, Trigg County, KY, Webster County, KY, Bollinger County, MO, Butler County, MO, Cape Girardeau County, MO, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Ripley County, MO, Scott County, MO, Stoddard County, MO, Wayne County, MO, Alcorn County, MS, Benton County, MS, DeSoto County, MS, Marshall County, MS, Prentiss County, MS, Tate County, MS, Tippah County, MS, Tishomingo 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, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Paducah radar (KPAH), 93 km from the middle of the area, began a volume at 18:40 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: 2%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

26 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 21, 2:05 PM CDT	Severe Thunderstorm Warning	MEG	Craighead, Poinsett	40 min
Jun 21, 2:10 PM CDT	Tornado Warning	MEG	Craighead, Poinsett	35 min
Jun 21, 2:16 PM CDT	Severe Thunderstorm Warning	PAH	Bollinger, Cape Girardeau, Scott, Stoddard	44 min
Jun 21, 2:22 PM CDT	Tornado Warning	PAH	Bollinger, Cape Girardeau	23 min
Jun 21, 2:43 PM CDT	Severe Thunderstorm Warning	MEG	Poinsett	32 min
Jun 21, 2:56 PM CDT	Severe Thunderstorm Warning	MEG	Poinsett	34 min
Jun 21, 3:18 PM CDT	Flash Flood Warning	MEG	Craighead, Poinsett	96 min
Jun 21, 3:29 PM CDT	Severe Thunderstorm Warning	MEG	Poinsett	31 min
Jun 21, 3:49 PM CDT	Severe Thunderstorm Warning	MEG	Mississippi	26 min
Jun 21, 4:01 PM CDT	Severe Thunderstorm Warning	MEG	Mississippi, Poinsett	44 min
Jun 21, 4:12 PM CDT	Severe Thunderstorm Warning	MEG	Pemiscot	20 min
Jun 21, 4:24 PM CDT	Severe Thunderstorm Warning	MEG	Mississippi	36 min
Jun 21, 4:51 PM CDT	Severe Thunderstorm Warning	MEG	Fayette, Shelby	24 min
Jun 21, 5:04 PM CDT	Severe Thunderstorm Warning	PAH	Livingston, Lyon, Marshall	26 min
Jun 21, 5:12 PM CDT	Severe Thunderstorm Warning	MEG	Fayette, Shelby	17 min
Jun 21, 5:27 PM CDT	Severe Thunderstorm Warning	MEG	Carroll, Crockett, Gibson, Henderson, Madison	48 min
Jun 21, 5:30 PM CDT	Severe Thunderstorm Warning	PAH	Caldwell, Lyon, Trigg	30 min
Jun 21, 6:03 PM CDT	Severe Thunderstorm Warning	MEG	Chester, Henderson, Madison	42 min
Jun 21, 6:11 PM CDT	Severe Thunderstorm Warning	MEG	Benton, Marshall, Tippah	49 min
Jun 21, 6:18 PM CDT	Severe Thunderstorm Warning	PAH	Christian, Todd	27 min
Jun 21, 6:28 PM CDT	Severe Thunderstorm Warning	MEG	Benton, Carroll, Decatur, Henderson	32 min
Jun 21, 6:36 PM CDT	Tornado Warning Tornado observed	PAH	Mississippi, New Madrid	24 min
Jun 21, 6:44 PM CDT	Severe Thunderstorm Warning	MEG	Alcorn, Tishomingo	46 min
Jun 21, 6:46 PM CDT	Severe Thunderstorm Warning	PAH	Todd	29 min
Jun 21, 8:10 PM CDT	Severe Thunderstorm Warning	MEG	Benton, Marshall	35 min
Jun 21, 8:37 PM CDT	Severe Thunderstorm Warning	MEG	Benton, Marshall, Tippah, Union	23 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 (KBYH), launched 12:00Z, 6.7 hours before the alert went out and 177 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

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

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 21, 12:31 PM CDT	Mesoscale Discussion	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 3 more	2 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

Severe Thunderstorm Watches in Tennessee, 2018 Severe Thunderstorm Watches in Kentucky, 2018 Severe Thunderstorm Watches in Arkansas, 2018 Every severe thunderstorm watch 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.