Alert archive / Tennessee / Mesoscale Discussions in 2013

Mesoscale Discussion 2102

December 21, 20134 states

The Storm Prediction Center issued this mesoscale discussion at Dec 21, 2013, 2:50 PM CST for 4 states. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Dec 21, 2013, 2:50 PM CST (20:50 UTC)
Expired: Dec 21, 2013, 3:45 PM CST
In force: 55 min
Issued by: the Storm Prediction Center

All 48 counties

Arkansas County, AR, Bradley County, AR, Crittenden County, AR, Cross County, AR, Desha County, AR, Drew County, AR, Lee County, AR, Lincoln County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, St. Francis County, AR, Dunklin County, MO, Pemiscot County, MO, Benton County, MS, Bolivar County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Lafayette County, MS, Leflore County, MS, Marshall County, MS, Panola County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Yalobusha County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Haywood County, TN, Henderson County, TN, Henry County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, Obion County, TN, Shelby County, TN, Stewart County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 92 km from the middle of the area, began a volume at 20:49 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, 8.8 hours before the alert went out and 47 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: 158 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 461 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 518 m²/s²
0-3 km storm-relative helicity: 610 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 20, 6:44 PM CST	Mesoscale Discussion	SPC	Clark, Dallas, Garland, Grant, Hempstead, Hot Spring and 11 more	91 min
Dec 20, 8:18 PM CST	Mesoscale Discussion	SPC	Benton	6 hr
Dec 20, 10:42 PM CST	Mesoscale Discussion	SPC	Miller	2 hr
Dec 21, 2:31 AM CST	Mesoscale Discussion	SPC	Clark, Clay, Cleburne, Columbia, Conway, Craighead and 30 more	2 hr
Dec 21, 7:57 AM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Cleveland, Columbia, Drew and 3 more	63 min
Dec 21, 9:46 AM CST	Tornado Watch	SPC	Ashley, Chicot, Columbia, Lafayette, Union	8 hr
Dec 21, 10:45 AM CST	Mesoscale Discussion	SPC	Arkansas, Bradley, Calhoun, Cleveland, Crittenden, Desha and 8 more	60 min
Dec 21, 12:01 PM CST	Tornado Watch	SPC	Arkansas, Bradley, Calhoun, Cleveland, Crittenden, Dallas and 10 more	8 hr
Dec 21, 12:30 PM CST	Mesoscale Discussion	SPC	Ashley, Chicot, Columbia, Lafayette, Union	60 min
Dec 21, 5:06 PM CST	Mesoscale Discussion	SPC	Adams, Alcorn, Amite, Attala, Benton, Bolivar and 47 more	84 min
Dec 21, 5:22 PM CST	Tornado Watch	SPC	Adams, Amite, Attala, Bolivar, Carroll, Choctaw and 40 more	7 hr
Dec 21, 5:46 PM CST	Tornado Watch	SPC	Alcorn, Benton, Calhoun, Chickasaw, Coahoma, DeSoto and 16 more	6 hr
Dec 21, 2:37 AM CST	Mesoscale Discussion	SPC	Audrain, Barton, Benton, Boone, Callaway, Camden and 32 more	4 hr
Dec 21, 12:53 PM CST	Mesoscale Discussion	SPC	Audrain, Barton, Bates, Benton, Boone, Callaway and 39 more	4 hr
Dec 21, 2:35 PM CST	Mesoscale Discussion	SPC	Andrew, Buchanan, Caldwell, Clay, Clinton, DeKalb and 4 more	4 hr

Nearby

Mesoscale Discussions in Tennessee, 2013 Mesoscale Discussions in Mississippi, 2013 Mesoscale Discussions in Arkansas, 2013 Every mesoscale discussion in 2013

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.