Alert archive / Arkansas / Mesoscale Discussions in 2013

Mesoscale Discussion 18

January 12, 20134 states

The Storm Prediction Center issued this mesoscale discussion at Jan 12, 2013, 6:18 PM CST for 4 states. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jan 12, 2013, 6:18 PM CST (00:18 UTC)
Expired: Jan 12, 2013, 8:15 PM CST
In force: 117 min
Issued by: the Storm Prediction Center

All 69 counties

Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Clay County, AR, Cleburne County, AR, Cleveland County, AR, Columbia County, AR, Conway County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Dallas County, AR, Drew County, AR, Faulkner County, AR, Garland County, AR, Grant County, AR, Greene County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Jefferson County, AR, Lafayette County, AR, Lawrence County, AR, Lee County, AR, Lincoln County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Mississippi County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Perry County, AR, Phillips County, AR, Pike County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, Sevier County, AR, Sharp County, AR, St. Francis County, AR, Stone County, AR, Union County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Bossier Parish, LA, Claiborne Parish, LA, Union Parish, LA, Webster Parish, LA, Butler County, MO, Dunklin County, MO, New Madrid County, MO, Pemiscot County, MO, Ripley County, MO, Stoddard County, MO, Bowie County, TX, Cass County, TX, Marion County, TX, Morris County, TX, Titus County, TX

The radar

The Little Rock radar (KLZK), 33 km from the middle of the area, began a volume at 00:22 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 (KLZK), launched 00:00Z, 0.3 hours before the alert went out and 207 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: 924 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 568 m above ground
0-6 km bulk shear: 74 kt
0-1 km storm-relative helicity: 485 m²/s²
0-3 km storm-relative helicity: 531 m²/s²
Significant tornado parameter: 3.3
Supercell composite: 15.7

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
Jan 12, 9:25 PM CST	Mesoscale Discussion	SPC	Arkansas, Bradley, Calhoun, Clark, Clay, Cleveland and 31 more	2 hr
Jan 12, 10:33 PM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Columbia, Drew, Ouachita and 1 more	87 min
Jan 12, 11:29 PM CST	Tornado Watch	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 9 more	5 hr
Jan 13, 1:18 AM CST	Mesoscale Discussion	SPC	Ashley, Chicot, Desha, Drew	87 min
Jan 13, 3:53 AM CST	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Chicot, Desha, Drew and 5 more	97 min
Jan 13, 2:30 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Lafourche, Livingston, Orleans, Saint Charles and 5 more	90 min
Jan 12, 6:17 PM CST	Mesoscale Discussion	SPC	Christian, Crawford, Dent, Douglas, Franklin, Gasconade and 22 more	6 hr

Nearby

Mesoscale Discussions in Arkansas, 2013 Mesoscale Discussions in Missouri, 2013 Mesoscale Discussions in Texas, 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.