Alert archive / Oklahoma / Mesoscale Discussions in 2011

Mesoscale Discussion 806

May 18, 201125 counties in Oklahoma

The Storm Prediction Center issued this mesoscale discussion at May 18, 2011, 6:48 PM CDT for 25 counties in Oklahoma. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
May 18, 2011, 6:48 PM CDT (23:48 UTC)
Expired
May 18, 2011, 8:15 PM CDT
In force
87 min
Issued by
the Storm Prediction Center
All 25 counties

Alfalfa County, OK, Blaine County, OK, Caddo County, OK, Canadian County, OK, Carter County, OK, Cleveland County, OK, Comanche County, OK, Cotton County, OK, Custer County, OK, Dewey County, OK, Garfield County, OK, Garvin County, OK, Grady County, OK, Grant County, OK, Harper County, OK, Jefferson County, OK, Kingfisher County, OK, Logan County, OK, Major County, OK, McClain County, OK, Murray County, OK, Oklahoma County, OK, Stephens County, OK, Woods County, OK, Woodward County, OK

The radar

The Vance AFB radar (KVNX), 123 km from the middle of the area, began a volume at 23:47 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 nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.8 hours before the alert went out and 137 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-pSkew-T log-p diagram, Norman, OK at 12:00Z on 2011-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 12:00Z on 2011-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 525 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
2 J/kg
Mixed-layer CIN
-612 J/kg
Mixed-layer LCL
934 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
525 m²/s²
0-3 km storm-relative helicity
713 m²/s²
Significant tornado parameter
0.0
Supercell composite
10.1

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.

IssuedProductOfficeCountiesLasted
May 18, 2:44 PM CDTMesoscale DiscussionSPCBlaine, Caddo, Canadian, Carter, Cleveland, Comanche and 13 more61 min
May 18, 3:48 PM CDTTornado WatchSPCAlfalfa, Blaine, Caddo, Canadian, Carter, Cleveland and 24 more3 hr

Nearby

Mesoscale Discussions in Oklahoma, 2011Every mesoscale discussion in 2011

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.