Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 76, NWS Norman, OK

April 9, 20215 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 9, 2021, 7:27 PM CDT for 5 counties in Oklahoma. It was in force for 33 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 9, 2021, 7:27 PM CDT (00:27 UTC)
Expired: Apr 9, 2021, 8:00 PM CDT
In force: 33 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 2.0 in
Wind: 60.0 mph

Counties Garvin County, OK, McClain County, OK, Pontotoc County, OK, Pottawatomie County, OK, Seminole County, OK

The radar

The Norman radar (KTLX), 73 km from the middle of the area, began a volume at 00:29 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 was reported inside it

Time	Report	Where
Apr 9, 7:45 PM CDT	HAIL 1	5 E Stratford, OK
Apr 9, 7:57 PM CDT	HAIL 1	4 W Ada, OK
Apr 9, 8:00 PM CDT	HAIL 1.75	Fitzhugh, OK

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

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 9, 3:55 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 0.5 hours before the alert went out and 72 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: 1392 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 1212 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.2

Open this sounding in Storm Lab

The text

As transmitted.

508 
WUUS54 KOUN 100027
SVROUN
OKC049-087-123-125-133-100100-
/O.NEW.KOUN.SV.W.0076.210410T0027Z-210410T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
727 PM CDT Fri Apr 9 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  Northeastern Garvin County in southern Oklahoma...
  Southern Seminole County in east central Oklahoma...
  Northwestern Pontotoc County in east central Oklahoma...
  South central Pottawatomie County in central Oklahoma...
  Southeastern McClain County in central Oklahoma...

* Until 800 PM CDT.

* At 726 PM CDT, severe thunderstorms were located along a line
  extending from 4 miles east of Asher to 7 miles east of Byars to 3
  miles west of Stratford, moving southeast at 35 mph.

  HAZARD...Two inch hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Ada, Stratford, Konawa, Byng, Roff, Asher, Francis, Byars,
  Fitzhugh, St. Louis, Sasakwa and Vanoss.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms are producing large hail. SEEK SHELTER NOW inside a
sturdy structure and stay away from windows!

&&

LAT...LON 3471 9663 3458 9681 3483 9713 3492 9700
      3508 9688 3502 9649 3485 9649
TIME...MOT...LOC 0026Z 304DEG 29KT 3498 9685 3488 9693 3481 9703 

HAIL...2.00IN
WIND...60MPH
 
$$

Mahale

1 follow-up statement

048 
WWUS54 KOUN 100047
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
747 PM CDT Fri Apr 9 2021

OKC087-100057-
/O.CAN.KOUN.SV.W.0076.000000T0000Z-210410T0100Z/
McClain OK-
747 PM CDT Fri Apr 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MCCLAIN COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3471 9663 3458 9681 3473 9700 3485 9691
      3506 9675 3502 9649 3485 9649
TIME...MOT...LOC 0047Z 303DEG 29KT 3499 9661 3479 9677 3472 9687 

$$

OKC049-123-125-133-100100-
/O.CON.KOUN.SV.W.0076.000000T0000Z-210410T0100Z/
Garvin OK-Seminole OK-Pontotoc OK-Pottawatomie OK-
747 PM CDT Fri Apr 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR EAST CENTRAL GARVIN...SOUTHERN SEMINOLE...NORTHWESTERN PONTOTOC
AND SOUTH CENTRAL POTTAWATOMIE COUNTIES...

At 747 PM CDT, severe thunderstorms were located along a line
extending from 5 miles northwest of Sasakwa to 6 miles west of Ada to
near Vanoss, moving southeast at 35 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Ada, Stratford, Konawa, Byng, Roff, Francis, Fitzhugh, Sasakwa and
Vanoss.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms are producing large hail. SEEK SHELTER NOW inside a
sturdy structure and stay away from windows.

&&

LAT...LON 3471 9663 3458 9681 3473 9700 3485 9691
      3506 9675 3502 9649 3485 9649
TIME...MOT...LOC 0047Z 303DEG 29KT 3499 9661 3479 9677 3472 9687 

HAIL...1.75IN
WIND...60MPH
 
$$

Mahale

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 9, 7:08 PM CDT	Severe Thunderstorm Warning	OUN	McClain, Pontotoc, Pottawatomie, Seminole	52 min
Apr 9, 7:35 PM CDT	Special Weather Statement	OUN	Marshall	25 min
Apr 9, 7:36 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Love, Marshall	39 min
Apr 9, 7:39 PM CDT	Severe Thunderstorm Warning	OUN	Hughes, Seminole	51 min
Apr 9, 7:51 PM CDT	Severe Thunderstorm Warning	OUN	Coal, Hughes, Johnston, Murray, Pontotoc, Seminole	54 min
Apr 9, 8:07 PM CDT	Severe Thunderstorm Warning	OUN	Love, Marshall	53 min
Apr 9, 8:11 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Coal, Johnston, Marshall, Murray, Pontotoc	34 min
Apr 9, 8:38 PM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan, Coal, Hughes, Johnston, Marshall	67 min
Apr 9, 9:15 PM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan, Marshall	60 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.