Alert archive / Texas / Mesoscale Discussions in 2020

Mesoscale Discussion 440

April 22, 202010 parishes in Louisiana; 11 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2020, 2:53 PM CDT for 10 parishes in Louisiana; 11 counties in Texas. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Apr 22, 2020, 2:53 PM CDT (19:53 UTC)
Expired
Apr 22, 2020, 4:00 PM CDT
In force
67 min
Issued by
the Storm Prediction Center
All 21 counties

Bienville Parish, LA, De Soto Parish, LA, Grant Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Winn Parish, LA, Anderson County, TX, Angelina County, TX, Cherokee County, TX, Houston County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Trinity County, TX

The radar

The Shreveport radar (KSHV), 78 km from the middle of the area, began a volume at 19:55 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.

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 7.9 hours before the alert went out and 81 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-pSkew-T log-p diagram, Shreveport, LA at 12:00Z on 2020-04-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 24 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2020-04-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 171 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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.

IssuedProductOfficeCountiesLasted
Apr 22, 10:38 AM CDTMesoscale DiscussionSPCCaddo, De Soto, Natchitoches, Red River, Sabine, Vernon2 hr
Apr 22, 10:55 AM CDTTornado WatchSPCAllen, Beauregard, De Soto, Evangeline, Grant, Natchitoches and 4 more6 hr
Apr 22, 1:10 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, De Soto, Evangeline, Grant and 6 more65 min
Apr 22, 4:24 PM CDTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 16 more96 min
Apr 22, 5:01 PM CDTTornado WatchSPCAllen, Avoyelles, Beauregard, Bienville, Bossier, Caddo and 17 more9 hr
Apr 22, 6:47 PM CDTMesoscale DiscussionSPCConcordia, Saint Helena, Tensas, Washington88 min
Apr 21, 8:12 PM CDTMesoscale DiscussionSPCHemphill, Lipscomb, Wheeler63 min
Apr 22, 1:21 AM CDTMesoscale DiscussionSPCFannin, Lamar, Red River84 min
Apr 22, 1:46 AM CDTSevere Thunderstorm WatchSPCFannin, Lamar, Red River4 hr
Apr 22, 2:16 AM CDTMesoscale DiscussionSPCCarson, Dallam, Hansford, Hartley, Hemphill, Hutchinson and 7 more119 min
Apr 22, 1:12 PM CDTMesoscale DiscussionSPCClay, Collin, Cooke, Dallas, Delta, Denton and 15 more63 min
Apr 22, 2:33 PM CDTTornado WatchSPCCollin, Cooke, Dallas, Delta, Denton, Fannin and 12 more6 hr
Apr 22, 4:43 PM CDTMesoscale DiscussionSPCGrayson62 min
Apr 22, 4:47 PM CDTMesoscale DiscussionSPCAngelina, Polk, San Augustine, San Jacinto, Trinity, Tyler and 1 more88 min
Apr 22, 5:38 PM CDTMesoscale DiscussionSPCCamp, Collin, Dallas, Delta, Fannin, Franklin and 10 more97 min
Apr 22, 5:53 PM CDTMesoscale DiscussionSPCAngelina, Polk, Trinity, Tyler37 min
Apr 22, 6:39 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Marion, Morris, Red River and 2 more66 min

Nearby

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