Alert archive / Oklahoma / Mesoscale Discussions in 2015

Mesoscale Discussion 818

May 28, 201517 counties in Oklahoma; 8 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 28, 2015, 2:50 AM CDT for 17 counties in Oklahoma; 8 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 28, 2015, 2:50 AM CDT (07:50 UTC)
Expired: May 28, 2015, 5:15 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 25 counties

Caddo County, OK, Carter County, OK, Comanche County, OK, Cotton County, OK, Garvin County, OK, Grady County, OK, Jackson County, OK, Jefferson County, OK, Johnston County, OK, Kiowa County, OK, Love County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Pontotoc County, OK, Stephens County, OK, Tillman County, OK, Archer County, TX, Clay County, TX, Cooke County, TX, Foard County, TX, Grayson County, TX, Montague County, TX, Wichita County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 61 km from the middle of the area, began a volume at 07:51 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, 7.8 hours before the alert went out and 143 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: 477 J/kg
Mixed-layer CIN: -199 J/kg
Mixed-layer LCL: 1424 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 28, 10:37 AM CDT	Mesoscale Discussion	SPC	LeFlore, McCurtain, Sequoyah	53 min
May 28, 2:18 PM CDT	Severe Thunderstorm Watch	SPC	Beaver, Cimarron, Texas	7 hr
May 28, 2:56 PM CDT	Mesoscale Discussion	SPC	Bryan, Carter, Coal, Comanche, Cotton, Garvin and 9 more	94 min
May 28, 3:26 PM CDT	Severe Thunderstorm Watch	SPC	Caddo, Canadian, Carter, Cleveland, Comanche, Cotton and 13 more	8 hr
May 28, 5:33 PM CDT	Mesoscale Discussion	SPC	Beaver, Cimarron, Harper, Texas	87 min
May 28, 11:45 AM CDT	Mesoscale Discussion	SPC	Andrews, Borden, Cochran, Cottle, Crosby, Dawson and 28 more	90 min
May 28, 12:44 PM CDT	Tornado Watch	SPC	Andrews, Bailey, Baylor, Borden, Brewster, Callahan and 58 more	7 hr
May 28, 2:04 PM CDT	Mesoscale Discussion	SPC	Atascosa, Austin, Bastrop, Bee, Bell, Bexar and 30 more	56 min
May 28, 3:42 PM CDT	Mesoscale Discussion	SPC	Andrews, Bailey, Baylor, Borden, Brewster, Cochran and 55 more	63 min
May 28, 6:57 PM CDT	Mesoscale Discussion	SPC	Bandera, Bexar, Blanco, Coke, Comal, Concho and 28 more	2 hr

Nearby

Mesoscale Discussions in Oklahoma, 2015 Mesoscale Discussions in Texas, 2015 Every mesoscale discussion in 2015

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.