Alert archive / Texas / Mesoscale Discussions in 2023

Mesoscale Discussion 69

January 18, 202311 counties in Arkansas; 6 parishes in Louisiana; 17 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jan 18, 2023, 7:28 AM CST for 11 counties in Arkansas; 6 parishes in Louisiana; 17 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jan 18, 2023, 7:28 AM CST (13:28 UTC)
Expired: Jan 18, 2023, 9:30 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 34 counties

Clark County, AR, Columbia County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Sevier County, AR, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Red River Parish, LA, Webster Parish, LA, Angelina County, TX, Bowie County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Houston County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Trinity County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 49 km from the middle of the area, began a volume at 13:29 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.

Tornado Watch 24Jan 18, 9:00 AM CST

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 1.5 hours before the alert went out and 58 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: 471 J/kg
Mixed-layer CIN: -73 J/kg
Mixed-layer LCL: 605 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 291 m²/s²
0-3 km storm-relative helicity: 275 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 3.1

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 18, 9:02 AM CST	Tornado Watch	SPC	Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 25 more	9 hr
Jan 18, 11:48 AM CST	Mesoscale Discussion	SPC	Bradley, Calhoun, Cleveland, Columbia, Dallas, Grant and 3 more	87 min
Jan 18, 12:30 PM CST	Mesoscale Discussion	SPC	Ashley, Chicot, Crittenden, Cross, Lee, Phillips and 1 more	90 min
Jan 18, 2:34 PM CST	Tornado Watch	SPC	Ashley, Chicot, Crittenden, Lee, Phillips, St. Francis	7 hr
Jan 18, 3:31 PM CST	Mesoscale Discussion	SPC	Ashley, Chicot, Desha	89 min
Jan 18, 5:47 PM CST	Mesoscale Discussion	SPC	Catahoula, Concordia, East Carroll, Franklin, Madison, Tensas	118 min

Nearby

Mesoscale Discussions in Texas, 2023 Mesoscale Discussions in Arkansas, 2023 Mesoscale Discussions in Louisiana, 2023 Every mesoscale discussion in 2023

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.