Alert archive / Oklahoma / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 538
The Storm Prediction Center issued this severe thunderstorm watch at Oct 26, 2021, 10:26 PM CDT for 9 counties in Kansas; 32 counties in Oklahoma. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 26, 2021, 10:26 PM CDT (03:26 UTC)
- Expired
- Oct 27, 2021, 5:00 AM CDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 41 counties
Butler County, KS, Chautauqua County, KS, Cowley County, KS, Harvey County, KS, Marion County, KS, McPherson County, KS, Saline County, KS, Sedgwick County, KS, Sumner County, KS, Atoka County, OK, Bryan County, OK, Canadian County, OK, Carter County, OK, Cleveland County, OK, Coal County, OK, Creek County, OK, Garfield County, OK, Garvin County, OK, Grant County, OK, Hughes County, OK, Johnston County, OK, Kay County, OK, Kingfisher County, OK, Lincoln County, OK, Logan County, OK, Love County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Noble County, OK, Okfuskee County, OK, Oklahoma County, OK, Okmulgee County, OK, Osage County, OK, Pawnee County, OK, Payne County, OK, Pontotoc County, OK, Pottawatomie County, OK, Seminole County, OK, Tulsa County, OK, Washington County, OK
The radar
The Vance AFB radar (KVNX), 113 km from the middle of the area, began a volume at 03:26 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 20%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 70%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 26, 11:22 PM CDT | Severe Thunderstorm Warning | OUN | Caddo, Canadian, Comanche, Garvin, Grady, McClain and 1 more | 38 min |
| Oct 26, 11:52 PM CDT | Severe Thunderstorm Warning | OUN | Blaine, Canadian, Cleveland, Garvin, Grady, Kingfisher and 3 more | 53 min |
| Oct 26, 11:53 PM CDT | Severe Thunderstorm Warning | OUN | Alfalfa, Garfield, Grant, Major | 52 min |
| Oct 27, 12:36 AM CDT | Tornado Warning | OUN | Cleveland, Lincoln, Oklahoma, Pottawatomie | 24 min |
| Oct 27, 12:43 AM CDT | Severe Thunderstorm Warning | OUN | Cleveland, Garvin, Lincoln, Logan, McClain, Oklahoma and 4 more | 47 min |
| Oct 27, 1:27 AM CDT | Severe Thunderstorm Warning | OUN | Coal, Garvin, Hughes, Lincoln, McClain, Payne and 3 more | 27 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Norman, OK (KOUN), launched 00:00Z, 3.4 hours before the alert went out and 171 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
- 791 J/kg
- Mixed-layer CIN
- -225 J/kg
- Mixed-layer LCL
- 916 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 277 m²/s²
- 0-3 km storm-relative helicity
- 380 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.5
The text
As transmitted.
702
WWUS20 KWNS 270323
SEL8
SPC WW 270323
KSZ000-OKZ000-271000-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 538
NWS Storm Prediction Center Norman OK
1025 PM CDT Tue Oct 26 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
South Central Kansas
Central Oklahoma
* Effective this Tuesday night and Wednesday morning from 1025 PM
until 500 AM CDT.
* Primary threats include...
Scattered damaging winds likely with isolated significant gusts
to 75 mph possible
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
A tornado or two possible
SUMMARY...Lines of strong to severe thunderstorms will track across
the watch area overnight, with the potential for damaging winds and
hail in the strongest cells. An isolated tornado spin-up or two is
also possible along the leading edge of these storms.
The severe thunderstorm watch area is approximately along and 50
statute miles east and west of a line from 55 miles northeast of
Hutchinson KS to 30 miles west southwest of Durant OK. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU8).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 536...WW 537...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
24040.
...HartSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 26, 8:59 PM CDT | Mesoscale Discussion | SPC | Barber, Barton, Clark, Comanche, Edwards, Ellis and 23 more | 91 min |
| Oct 26, 10:09 PM CDT | Mesoscale Discussion | SPC | Butler, Chase, Chautauqua, Cowley, Elk, Greenwood and 7 more | 66 min |
| Oct 26, 7:23 PM CDT | Severe Thunderstorm Watch | SPC | Caddo, Comanche, Cotton, Grady, Greer, Harmon and 5 more | 8 hr |
| Oct 26, 9:37 PM CDT | Mesoscale Discussion | SPC | Beckham, Caddo, Comanche, Cotton, Grady, Greer and 5 more | 83 min |
| Oct 27, 1:13 AM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Coal, Creek, Hughes, Johnston and 15 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Oklahoma, 2021Severe Thunderstorm Watches in Kansas, 2021Every severe thunderstorm watch 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.