Alert archive / Oklahoma / Mesoscale Discussions in 2007

Mesoscale Discussion 1794

August 18, 200714 counties in Oklahoma; Clay County, Texas

The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2007, 5:34 PM CDT for 14 counties in Oklahoma; Clay County, Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 18, 2007, 5:34 PM CDT (22:34 UTC)
Expired: Aug 18, 2007, 8:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Blaine County, OK, Caddo County, OK, Canadian County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Garvin County, OK, Grady County, OK, Jefferson County, OK, McClain County, OK, Oklahoma County, OK, Stephens County, OK, Washita County, OK, Clay County, TX

The radar

The Altus AFB radar (KFDR), 79 km from the middle of the area, began a volume at 22:34 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

Lamont, OK (KLMN), launched 12:00Z, 10.6 hours before the alert went out and 219 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: 1691 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 790 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: -7 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Aug 18, 7:55 AM CDT	Mesoscale Discussion	SPC	Beaver, Beckham, Ellis, Greer, Harmon, Harper and 3 more	2 hr
Aug 17, 11:13 PM CDT	Mesoscale Discussion	SPC	Coke, Fisher, Foard, Haskell, Jones, Kent and 10 more	3 hr

Nearby

Mesoscale Discussions in Oklahoma, 2007 Mesoscale Discussions in Texas, 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.