Alert archive / Oklahoma / Mesoscale Discussions in 2018

Mesoscale Discussion 420

May 14, 2018Harper County, Kansas; 17 counties in Oklahoma; 11 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 14, 2018, 8:05 PM CDT for Harper County, Kansas; 17 counties in Oklahoma; 11 counties in Texas. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 14, 2018, 8:05 PM CDT (01:05 UTC)
Expired: May 14, 2018, 9:30 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center

All 29 counties

Harper County, KS, Alfalfa County, OK, Beckham County, OK, Blaine County, OK, Caddo County, OK, Custer County, OK, Dewey County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Kingfisher County, OK, Kiowa County, OK, Major County, OK, Roger Mills County, OK, Tillman County, OK, Washita County, OK, Woods County, OK, Woodward County, OK, Childress County, TX, Collingsworth County, TX, Cottle County, TX, Dickens County, TX, Foard County, TX, Hall County, TX, Hardeman County, TX, King County, TX, Knox County, TX, Motley County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 77 km from the middle of the area, began a volume at 01:05 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

Norman, OK (KOUN), launched 00:00Z, 1.1 hours before the alert went out and 190 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: 2133 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 1290 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 42 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.1

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
May 14, 7:15 PM CDT	Mesoscale Discussion	SPC	Allen, Anderson, Bourbon, Butler, Chase, Chautauqua and 19 more	90 min
May 14, 8:32 PM CDT	Mesoscale Discussion	SPC	Finney, Hodgeman, Lane, Ness, Scott, Wichita	88 min
May 14, 11:30 PM CDT	Mesoscale Discussion	SPC	Cherokee, Labette	90 min
May 15, 11:31 AM CDT	Mesoscale Discussion	SPC	Carter, Cleveland, Coal, Garvin, Grady, Johnston and 5 more	119 min
May 15, 2:32 PM CDT	Mesoscale Discussion	SPC	Cimarron	118 min
May 15, 3:17 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Choctaw, Coal, Johnston, Love and 5 more	88 min
May 15, 5:17 PM CDT	Severe Thunderstorm Watch	SPC	Cimarron, Texas	8 hr
May 15, 1:51 PM CDT	Mesoscale Discussion	SPC	Borden, Coke, Crockett, Crosby, Dawson, Dickens and 22 more	114 min

Nearby

Mesoscale Discussions in Oklahoma, 2018 Mesoscale Discussions in Texas, 2018 Mesoscale Discussions in Kansas, 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.