Alert archive / Oklahoma / Mesoscale Discussions in 2020

Mesoscale Discussion 437

April 22, 2020Sebastian County, Arkansas; 11 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Apr 22, 2020, 11:29 AM CDT for Sebastian County, Arkansas; 11 counties in Oklahoma. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Apr 22, 2020, 11:29 AM CDT (16:29 UTC)
Expired: Apr 22, 2020, 1:00 PM CDT
In force: 91 min
Issued by: the Storm Prediction Center

Counties Sebastian County, AR, Atoka County, OK, Coal County, OK, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, McIntosh County, OK, Muskogee County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK

The radar

The Western Arkansas radar (KSRX), 112 km from the middle of the area, began a volume at 16:32 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 134Apr 22, 2:35 PM CDT

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 4.5 hours before the alert went out and 180 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: 20 J/kg
Mixed-layer CIN: -449 J/kg
Mixed-layer LCL: 1138 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 375 m²/s²
0-3 km storm-relative helicity: 455 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

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, 1:46 AM CDT	Severe Thunderstorm Watch	SPC	Howard, Little River, Sevier	4 hr
Apr 22, 8:53 AM CDT	Severe Thunderstorm Watch	SPC	Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more	6 hr
Apr 22, 6:39 PM CDT	Mesoscale Discussion	SPC	Clark, Columbia, Hempstead, Howard, Lafayette, Little River and 6 more	66 min
Apr 21, 9:10 PM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Caddo, Canadian, Carter, Cleveland and 24 more	95 min
Apr 21, 11:32 PM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Caddo, Canadian, Carter, Cleveland and 24 more	88 min
Apr 22, 1:21 AM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Carter, Choctaw, Coal, Garvin and 7 more	84 min
Apr 22, 2:16 AM CDT	Mesoscale Discussion	SPC	Beaver, Ellis, Harper, Texas, Woods, Woodward	119 min
Apr 22, 8:36 AM CDT	Mesoscale Discussion	SPC	Atoka, Blaine, Caddo, Canadian, Carter, Cleveland and 26 more	84 min
Apr 22, 1:12 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Carter, Choctaw, Coal, Garvin and 7 more	63 min
Apr 22, 2:33 PM CDT	Tornado Watch	SPC	Atoka, Bryan, Carter, Choctaw, Coal, Garvin and 11 more	6 hr
Apr 22, 4:43 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Coal, Garvin, Johnston, Marshall and 2 more	62 min

Nearby

Mesoscale Discussions in Oklahoma, 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.