Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 111, NWS Norman, OK

April 23, 20214 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 23, 2021, 8:24 PM CDT for 4 counties in Oklahoma. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Apr 23, 2021, 8:24 PM CDT (01:24 UTC)
Expired: Apr 23, 2021, 9:15 PM CDT
In force: 51 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Garvin County, OK, Grady County, OK, McClain County, OK, Stephens County, OK

The radar

The Norman radar (KTLX), 91 km from the middle of the area, began a volume at 01:25 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 23, 8:02 PM CDT	Severe Thunderstorm Watch	SPC	4 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 1.4 hours before the alert went out and 74 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: 486 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 504 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 345 m²/s²
0-3 km storm-relative helicity: 408 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 6.8

Open this sounding in Storm Lab

The text

As transmitted.

135 
WUUS54 KOUN 240124
SVROUN
OKC049-051-087-137-240215-
/O.NEW.KOUN.SV.W.0111.210424T0124Z-210424T0215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
824 PM CDT Fri Apr 23 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  Western Garvin County in southern Oklahoma...
  Southeastern Grady County in central Oklahoma...
  Northeastern Stephens County in southern Oklahoma...
  Southwestern McClain County in central Oklahoma...

* Until 915 PM CDT.

* At 823 PM CDT, severe thunderstorms were located along a line
  extending from 4 miles southeast of Agawam to 5 miles southeast of
  Duncan, moving east at 30 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Duncan, Marlow, Lindsay, Rush Springs, Bray, Velma, Alex, Bradley,
  Agawam, Cox City and Erin Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3447 9799 3490 9798 3498 9757 3441 9756
TIME...MOT...LOC 0123Z 261DEG 25KT 3483 9788 3446 9792 

HAIL...1.00IN
WIND...60MPH
 
$$

TL

1 follow-up statement

018 
WWUS54 KOUN 240149
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
849 PM CDT Fri Apr 23 2021

OKC049-051-087-137-240215-
/O.CON.KOUN.SV.W.0111.000000T0000Z-210424T0215Z/
Garvin OK-Grady OK-Stephens OK-McClain OK-
849 PM CDT Fri Apr 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM CDT
FOR WESTERN GARVIN...SOUTHEASTERN GRADY...NORTHEASTERN STEPHENS AND
SOUTHWESTERN MCCLAIN COUNTIES...

At 848 PM CDT, severe thunderstorms were located along a line
extending from 3 miles southeast of Bradley to 8 miles west of Velma,
moving east at 30 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Duncan, Lindsay, Bray, Velma, Alex, Bradley, Cox City and Erin
Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3447 9799 3493 9781 3498 9757 3441 9756
TIME...MOT...LOC 0148Z 261DEG 24KT 3484 9767 3449 9780 

HAIL...1.00IN
WIND...60MPH
 
$$

TL

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 23, 7:06 PM CDT	Severe Thunderstorm Warning	OUN	Harmon, Jackson	39 min
Apr 23, 7:15 PM CDT	Special Weather Statement	OUN	Garfield	30 min
Apr 23, 7:24 PM CDT	Special Weather Statement	OUN	Comanche	36 min
Apr 23, 7:52 PM CDT	Severe Thunderstorm Warning	OUN	Cotton	37 min
Apr 23, 8:00 PM CDT	Special Weather Statement	OUN	Grady	30 min
Apr 23, 8:04 PM CDT	Special Weather Statement	OUN	Stephens	26 min
Apr 23, 8:18 PM CDT	Severe Thunderstorm Warning	OUN	Cotton, Jefferson	42 min
Apr 23, 8:36 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson, Stephens	39 min
Apr 23, 8:44 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson	31 min
Apr 23, 8:53 PM CDT	Special Weather Statement	OUN	Cleveland, McClain	37 min
Apr 23, 8:59 PM CDT	Special Weather Statement	OUN	Garvin	31 min
Apr 23, 9:02 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson	43 min
Apr 23, 9:12 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Jefferson, Love, Murray, Stephens	48 min
Apr 23, 9:29 PM CDT	Special Weather Statement	OUN	Cleveland, Garvin, Pottawatomie	31 min
Apr 23, 10:00 PM CDT	Special Weather Statement	OUN	Carter, Murray, Pontotoc, Pottawatomie, Seminole	30 min
Apr 23, 10:29 PM CDT	Special Weather Statement	OUN	Coal, Hughes, Johnston, Love, Marshall, Pontotoc and 1 more	31 min
Apr 23, 11:00 PM CDT	Special Weather Statement	OUN	Atoka, Bryan, Coal, Hughes, Marshall, Seminole	30 min
Apr 23, 11:08 PM CDT	Areal Flood Advisory	OUN	Atoka, Bryan	3 hr

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2021 Every severe thunderstorm warning 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.