Alert archive / Oklahoma / Mesoscale Discussions in 2004

Mesoscale Discussion 394

April 20, 20044 states

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2004, 5:16 PM CDT for 4 states. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Apr 20, 2004, 5:16 PM CDT (22:16 UTC)
Expired: Apr 20, 2004, 7:15 PM CDT
In force: 119 min
Issued by: the Storm Prediction Center

All 44 counties

Benton County, AR, Washington County, AR, Allen County, KS, Bourbon County, KS, Butler County, KS, Chautauqua County, KS, Cherokee County, KS, Cowley County, KS, Crawford County, KS, Elk County, KS, Greenwood County, KS, Labette County, KS, Montgomery County, KS, Neosho County, KS, Wilson County, KS, Woodson County, KS, Barry County, MO, Barton County, MO, Cedar County, MO, Dade County, MO, Jasper County, MO, Lawrence County, MO, McDonald County, MO, Newton County, MO, St. Clair County, MO, Vernon County, MO, Adair County, OK, Cherokee County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Kay County, OK, Lincoln County, OK, Mayes County, OK, Nowata County, OK, Okmulgee County, OK, Osage County, OK, Ottawa County, OK, Pawnee County, OK, Payne County, OK, Rogers County, OK, Tulsa County, OK, Wagoner County, OK, Washington County, OK

The radar

The Tulsa radar (KINX), 70 km from the middle of the area, began a volume at 22:18 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.

Tornado Watch 97Apr 20, 7:50 PM CDT

The nearest sounding before it

Lamont, OK (KLMN), launched 12:00Z, 10.3 hours before the alert went out and 213 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: 5 J/kg
Mixed-layer CIN: -347 J/kg
Mixed-layer LCL: 913 m above ground
0-6 km bulk shear: 71 kt
0-1 km storm-relative helicity: 214 m²/s²
0-3 km storm-relative helicity: 320 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
Apr 20, 2:05 PM CDT	Tornado Watch	SPC	Benton, Madison, Washington	6 hr
Apr 19, 9:00 PM CDT	Severe Thunderstorm Watch	SPC	Barber, Barton, Clark, Comanche, Edwards, Ellis and 28 more	5 hr
Apr 19, 11:04 PM CDT	Mesoscale Discussion	SPC	Barber, Barton, Clark, Comanche, Edwards, Ellis and 28 more	86 min
Apr 20, 12:47 PM CDT	Mesoscale Discussion	SPC	Chautauqua, Cherokee, Cowley, Elk, Labette, Montgomery and 4 more	88 min
Apr 20, 4:40 PM CDT	Severe Thunderstorm Watch	SPC	Adair, Audrain, Bates, Benton, Boone, Caldwell and 37 more	5 hr
Apr 20, 6:25 PM CDT	Severe Thunderstorm Watch	SPC	Atchison	5 hr
Apr 19, 7:53 PM CDT	Mesoscale Discussion	SPC	Beaver, Cimarron, Texas	67 min
Apr 20, 5:46 PM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Carter, Coal, Garvin, Haskell and 13 more	89 min

Nearby

Mesoscale Discussions in Oklahoma, 2004 Mesoscale Discussions in Kansas, 2004 Mesoscale Discussions in Missouri, 2004 Every mesoscale discussion in 2004

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.