Alert archive / Oklahoma / Mesoscale Discussions in 2007

Mesoscale Discussion 534

April 21, 2007Barber County, Comanche County, Kansas; 20 counties in Oklahoma; 12 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2007, 10:45 PM CDT for Barber County, Comanche County, Kansas; 20 counties in Oklahoma; 12 counties in Texas. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Apr 21, 2007, 10:45 PM CDT (03:45 UTC)
Expired: Apr 21, 2007, 11:45 PM CDT
In force: 60 min
Issued by: the Storm Prediction Center

All 34 counties

Barber County, KS, Comanche County, KS, Alfalfa County, OK, Beaver County, OK, Beckham County, OK, Blaine County, OK, Caddo County, OK, Comanche County, OK, Custer County, OK, Dewey County, OK, Ellis County, OK, Greer County, OK, Harmon County, OK, Harper County, OK, Jackson 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, Foard County, TX, Hall County, TX, Hardeman County, TX, Hemphill County, TX, Lipscomb County, TX, Ochiltree County, TX, Roberts County, TX, Wheeler County, TX, Wilbarger County, TX

The radar

The Altus AFB radar (KFDR), 155 km from the middle of the area, began a volume at 03:47 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.

Severe Thunderstorm Watch 161Apr 21, 11:00 PM CDT

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 00:00Z, 3.8 hours before the alert went out and 207 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: 1794 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 946 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 263 m²/s²
0-3 km storm-relative helicity: 301 m²/s²
Significant tornado parameter: 3.3
Supercell composite: 16.9

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
Apr 22, 10:57 AM CDT	Mesoscale Discussion	SPC	Atchison, Brown, Clay, Cloud, Dickinson, Doniphan and 20 more	93 min
Apr 22, 11:30 AM CDT	Tornado Watch	SPC	Atchison, Brown, Clay, Cloud, Doniphan, Geary and 10 more	6 hr
Apr 22, 3:07 PM CDT	Mesoscale Discussion	SPC	Allen, Anderson, Bourbon, Cherokee, Coffey, Crawford and 13 more	113 min
Apr 21, 7:41 PM CDT	Mesoscale Discussion	SPC	Beaver, Cimarron, Texas	2 hr
Apr 21, 11:02 PM CDT	Severe Thunderstorm Watch	SPC	Beckham, Custer, Dewey, Ellis, Greer, Harmon and 8 more	3 hr
Apr 22, 3:51 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Carter, Coal, Creek, Garvin and 18 more	2 hr

Nearby

Mesoscale Discussions in Oklahoma, 2007 Mesoscale Discussions in Texas, 2007 Mesoscale Discussions in Kansas, 2007 Every mesoscale discussion in 2007

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.