Alert archive / Oklahoma / Mesoscale Discussions in 2011
Mesoscale Discussion 505
The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2011, 2:25 PM CDT for 25 counties in Arkansas; Chautauqua County, Labette County, Montgomery County, Kansas; 27 counties in Oklahoma. It was in force for 65 min.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2011, 2:25 PM CDT (19:25 UTC)
- Expired
- Apr 21, 2011, 3:30 PM CDT
- In force
- 65 min
- Issued by
- the Storm Prediction Center
All 55 counties
Benton County, AR, Clark County, AR, Conway County, AR, Crawford County, AR, Dallas County, AR, Franklin County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Howard County, AR, Johnson County, AR, Logan County, AR, Madison County, AR, Montgomery County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Sebastian County, AR, Sevier County, AR, Washington County, AR, Yell County, AR, Chautauqua County, KS, Labette County, KS, Montgomery County, KS, Adair County, OK, Cherokee County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Haskell County, OK, Hughes County, OK, Latimer County, OK, LeFlore County, OK, Mayes County, OK, McCurtain County, OK, McIntosh County, OK, Muskogee County, OK, Nowata County, OK, Okfuskee County, OK, Okmulgee County, OK, Osage County, OK, Ottawa County, OK, Pawnee County, OK, Pittsburg County, OK, Pushmataha County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK, Washington County, OK
The radar
The Western Arkansas radar (KSRX), 26 km from the middle of the area, began a volume at 19:25 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.
The nearest sounding before it
Springfield, MO (KSGF), launched 12:00Z, 7.4 hours before the alert went out and 167 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1583 m above ground
- 0-6 km bulk shear
- 60 kt
- 0-1 km storm-relative helicity
- 68 m²/s²
- 0-3 km storm-relative helicity
- 289 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 20, 7:45 PM CDT | Severe Thunderstorm Watch | SPC | Ashley, Chicot | 6 hr |
| Apr 20, 10:22 PM CDT | Mesoscale Discussion | SPC | Ashley, Bradley, Chicot, Desha, Drew, Lincoln | 83 min |
| Apr 21, 2:35 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Benton, Boone, Carroll, Clark, Conway and 22 more | 7 hr |
| Apr 21, 6:13 PM CDT | Mesoscale Discussion | SPC | Benton, Crawford, Franklin, Garland, Johnson, Logan and 7 more | 92 min |
Nearby
Mesoscale Discussions in Oklahoma, 2011Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Kansas, 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.