Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 474

April 24, 2020Columbia County, Lafayette County, Miller County, Arkansas; 5 parishes in Louisiana; 4 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2020, 9:26 PM CDT for Columbia County, Lafayette County, Miller County, Arkansas; 5 parishes in Louisiana; 4 counties in Texas. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Apr 24, 2020, 9:26 PM CDT (02:26 UTC)
Expired: Apr 24, 2020, 11:00 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center

Counties Columbia County, AR, Lafayette County, AR, Miller County, AR, Bossier Parish, LA, Caddo Parish, LA, De Soto Parish, LA, Red River Parish, LA, Webster Parish, LA, Cass County, TX, Harrison County, TX, Marion County, TX, Panola County, TX

The radar

The Shreveport radar (KSHV), 12 km from the middle of the area, began a volume at 02:26 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 (KSHV), launched 00:00Z, 2.4 hours before the alert went out and 13 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: 319 J/kg
Mixed-layer CIN: -165 J/kg
Mixed-layer LCL: 1943 m above ground
0-6 km bulk shear: 72 kt
0-1 km storm-relative helicity: 160 m²/s²
0-3 km storm-relative helicity: 350 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 6.1

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
Apr 24, 7:19 PM CDT	Mesoscale Discussion	SPC	Clark, Columbia, Hempstead, Howard, Lafayette, Little River and 6 more	101 min
Apr 24, 8:31 PM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Ashley, Boone, Bradley, Calhoun, Chicot and 30 more	5 hr
Apr 24, 10:17 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Baxter, Bradley, Calhoun, Chicot and 29 more	118 min
Apr 24, 7:43 PM CDT	Mesoscale Discussion	SPC	Bienville, Caldwell, Claiborne, Grant, Jackson, Lincoln and 6 more	62 min

Nearby

Mesoscale Discussions in Louisiana, 2020 Mesoscale Discussions in Texas, 2020 Mesoscale Discussions in Arkansas, 2020 Every mesoscale discussion in 2020

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.