Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 441

April 22, 202022 parishes in Louisiana; Adams County, Mississippi; 20 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2020, 4:24 PM CDT for 22 parishes in Louisiana; Adams County, Mississippi; 20 counties in Texas. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2020, 4:24 PM CDT (21:24 UTC)
Expired: Apr 22, 2020, 6:00 PM CDT
In force: 96 min
Issued by: the Storm Prediction Center

All 43 counties

Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Vernon Parish, LA, Winn Parish, LA, Adams County, MS, Angelina County, TX, Brazos County, TX, Cherokee County, TX, Grimes County, TX, Hardin County, TX, Houston County, TX, Jasper County, TX, Liberty County, TX, Madison County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX

The radar

The Ft Polk radar (KPOE), 71 km from the middle of the area, began a volume at 21:28 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 135Apr 22, 5:00 PM CDT

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 9.4 hours before the alert went out and 130 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: 24 J/kg
Mixed-layer CIN: -457 J/kg
Mixed-layer LCL: 1104 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 379 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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 22, 10:38 AM CDT	Mesoscale Discussion	SPC	Caddo, De Soto, Natchitoches, Red River, Sabine, Vernon	2 hr
Apr 22, 10:55 AM CDT	Tornado Watch	SPC	Allen, Beauregard, De Soto, Evangeline, Grant, Natchitoches and 4 more	6 hr
Apr 22, 1:10 PM CDT	Mesoscale Discussion	SPC	Allen, Beauregard, Calcasieu, De Soto, Evangeline, Grant and 6 more	65 min
Apr 22, 2:53 PM CDT	Mesoscale Discussion	SPC	Bienville, De Soto, Grant, LaSalle, Natchitoches, Rapides and 4 more	67 min
Apr 22, 5:01 PM CDT	Tornado Watch	SPC	Allen, Avoyelles, Beauregard, Bienville, Bossier, Caddo and 17 more	9 hr
Apr 22, 6:47 PM CDT	Mesoscale Discussion	SPC	Concordia, Saint Helena, Tensas, Washington	88 min
Apr 21, 8:12 PM CDT	Mesoscale Discussion	SPC	Hemphill, Lipscomb, Wheeler	63 min
Apr 22, 1:21 AM CDT	Mesoscale Discussion	SPC	Fannin, Lamar, Red River	84 min
Apr 22, 1:46 AM CDT	Severe Thunderstorm Watch	SPC	Fannin, Lamar, Red River	4 hr
Apr 22, 2:16 AM CDT	Mesoscale Discussion	SPC	Carson, Dallam, Hansford, Hartley, Hemphill, Hutchinson and 7 more	119 min
Apr 22, 1:12 PM CDT	Mesoscale Discussion	SPC	Clay, Collin, Cooke, Dallas, Delta, Denton and 15 more	63 min
Apr 22, 2:33 PM CDT	Tornado Watch	SPC	Collin, Cooke, Dallas, Delta, Denton, Fannin and 12 more	6 hr
Apr 22, 4:43 PM CDT	Mesoscale Discussion	SPC	Grayson	62 min
Apr 22, 4:47 PM CDT	Mesoscale Discussion	SPC	Angelina, Polk, San Augustine, San Jacinto, Trinity, Tyler and 1 more	88 min
Apr 22, 5:38 PM CDT	Mesoscale Discussion	SPC	Camp, Collin, Dallas, Delta, Fannin, Franklin and 10 more	97 min
Apr 22, 5:53 PM CDT	Mesoscale Discussion	SPC	Angelina, Polk, Trinity, Tyler	37 min
Apr 22, 6:39 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Marion, Morris, Red River and 2 more	66 min

Nearby

Mesoscale Discussions in Louisiana, 2020 Mesoscale Discussions in Texas, 2020 Mesoscale Discussions in Mississippi, 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.