Alert archive / Oklahoma / Mesoscale Discussions in 2012

Mesoscale Discussion 1784

August 18, 201211 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at Aug 18, 2012, 9:29 AM CDT for 11 counties in Oklahoma. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Aug 18, 2012, 9:29 AM CDT (14:29 UTC)
Expired: Aug 18, 2012, 11:00 AM CDT
In force: 91 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Alfalfa County, OK, Blaine County, OK, Canadian County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Kingfisher County, OK, Logan County, OK, Major County, OK, Woods County, OK, Woodward County, OK

The radar

The Vance AFB radar (KVNX), 64 km from the middle of the area, began a volume at 14:30 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, 2.5 hours before the alert went out and 106 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1630 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 99 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, 3:52 AM CDT	Mesoscale Discussion	SPC	Alfalfa, Beaver, Ellis, Harper, Woods, Woodward	113 min
Aug 18, 1:10 PM CDT	Mesoscale Discussion	SPC	Cotton, Jackson, Tillman	2 hr
Aug 18, 2:05 PM CDT	Severe Thunderstorm Watch	SPC	Cotton, Jefferson, Tillman	7 hr
Aug 18, 5:00 PM CDT	Mesoscale Discussion	SPC	Cotton, Jefferson, Tillman	90 min

Nearby

Mesoscale Discussions in Oklahoma, 2012 Every mesoscale discussion in 2012

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.