Alert archive / Louisiana / Mesoscale Discussions in 2018

Mesoscale Discussion 1193

July 29, 20184 counties in Arkansas; 16 parishes in Louisiana; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Jul 29, 2018, 1:22 PM CDT for 4 counties in Arkansas; 16 parishes in Louisiana; 15 counties in Texas. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Jul 29, 2018, 1:22 PM CDT (18:22 UTC)
Expired: Jul 29, 2018, 2:45 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 35 counties

Columbia County, AR, Lafayette County, AR, Miller County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Angelina County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Upshur County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 21 km from the middle of the area, began a volume at 18:23 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

Shreveport, LA (KBAD), launched 12:00Z, 6.4 hours before the alert went out and 25 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: 662 J/kg
Mixed-layer CIN: -119 J/kg
Mixed-layer LCL: 1046 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 111 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Jul 28, 11:10 PM CDT	Mesoscale Discussion	SPC	Lipscomb	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2018 Mesoscale Discussions in Texas, 2018 Mesoscale Discussions in Arkansas, 2018 Every 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.