Alert archive / Oklahoma / Mesoscale Discussions in 2021
Mesoscale Discussion 1827
The Storm Prediction Center issued this mesoscale discussion at Oct 10, 2021, 11:32 PM CDT for 4 states. It was in force for 118 min.
The area
The outline as issued.
The facts
- Issued
- Oct 10, 2021, 11:32 PM CDT (04:32 UTC)
- Expired
- Oct 11, 2021, 1:30 AM CDT
- In force
- 118 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 519
All 33 counties
Benton County, AR, Crawford County, AR, Polk County, AR, Scott County, AR, Sebastian County, AR, Sevier County, AR, Washington County, AR, Cherokee County, KS, Labette County, KS, Montgomery County, KS, Jasper County, MO, McDonald County, MO, Newton County, MO, Adair County, OK, Cherokee County, OK, Choctaw County, OK, Craig County, OK, Delaware County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, Mayes County, OK, McCurtain County, OK, McIntosh County, OK, Muskogee County, OK, Nowata County, OK, Ottawa County, OK, Pittsburg County, OK, Pushmataha County, OK, Rogers County, OK, Sequoyah County, OK, Wagoner County, OK, Washington County, OK
The radar
The Western Arkansas radar (KSRX), 70 km from the middle of the area, began a volume at 04:36 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 00:00Z, 4.5 hours before the alert went out and 206 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
- 1436 J/kg
- Mixed-layer CIN
- -35 J/kg
- Mixed-layer LCL
- 1199 m above ground
- 0-6 km bulk shear
- 71 kt
- 0-1 km storm-relative helicity
- 187 m²/s²
- 0-3 km storm-relative helicity
- 255 m²/s²
- Significant tornado parameter
- 1.9
- Supercell composite
- 8.8
The text
As transmitted.
084 ACUS11 KWNS 110432 SWOMCD SPC MCD 110432 ARZ000-MOZ000-OKZ000-KSZ000-TXZ000-110630- Mesoscale Discussion 1827 NWS Storm Prediction Center Norman OK 1132 PM CDT Sun Oct 10 2021 Areas affected...Eastern OK...Southeast KS...Southwest MO...Western AR Concerning...Tornado Watch 519... Valid 110432Z - 110630Z The severe weather threat for Tornado Watch 519 continues. SUMMARY...Severe threat will continue shifting east across the remainder of ww519 over the next several hours. DISCUSSION...LLJ is strengthening along the OK/AR border late this evening. As a result, low-level shear is quite strong across the warm sector where adequate buoyancy continues to reside. Latest diagnostic data suggests the current squall line is advancing through the instability axis and subsequent movement appreciably east of the current watch should result in weaker updrafts due to lower boundary-layer dew points. However, stronger updrafts along the squall line, that extends across eastern OK, continue to exhibit transient supercellular characteristics at times. These features have been mostly responsible for brief tornado reports as the squall line advances east. These robust structures will likely persist until convection propagates east of the greater buoyancy, east of ww519. ..Darrow.. 10/11/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SGF...SHV...TSA...ICT...FWD...OUN... LAT...LON 33859590 37499593 37499394 33849400 33859590
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 10, 9:24 PM CDT | Tornado Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 5 hr |
| Oct 10, 10:16 PM CDT | Mesoscale Discussion | SPC | Little River, Polk, Sevier | 59 min |
| Oct 10, 11:07 PM CDT | Tornado Watch | SPC | Hempstead, Howard, Lafayette, Little River, Logan, Miller and 6 more | 5 hr |
| Oct 11, 12:58 AM CDT | Mesoscale Discussion | SPC | Hempstead, Howard, Lafayette, Little River, Logan, Miller and 5 more | 92 min |
| Oct 11, 1:26 AM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 64 min |
| Oct 10, 7:19 PM CDT | Mesoscale Discussion | SPC | Allen, Bourbon, Chautauqua, Cherokee, Crawford, Elk and 5 more | 86 min |
| Oct 11, 5:00 AM CDT | Mesoscale Discussion | SPC | Cedar, Christian, Dade, Dallas, Greene, Hickory and 7 more | 2 hr |
| Oct 11, 9:06 AM CDT | Mesoscale Discussion | SPC | Audrain, Callaway, Franklin, Gasconade, Jefferson, Lincoln and 11 more | 2 hr |
| Oct 10, 8:11 PM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Coal, Johnston, Love and 1 more | 64 min |
Nearby
Mesoscale Discussions in Oklahoma, 2021Mesoscale Discussions in Arkansas, 2021Mesoscale Discussions in Kansas, 2021Every mesoscale discussion in 2021
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.