Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 458, NWS Norman, OK

August 19, 2021Greer County, Harmon County, Oklahoma; Hardeman County, Texas

NWS Norman, OK issued this severe thunderstorm warning at Aug 19, 2021, 4:59 PM CDT for Greer County, Harmon County, Oklahoma; Hardeman County, Texas. It was in force for 31 min. 2 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: Aug 19, 2021, 4:59 PM CDT (21:59 UTC)
Expired: Aug 19, 2021, 5:30 PM CDT
In force: 31 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 0.88 in
Wind: 60.0 mph

Counties Greer County, OK, Harmon County, OK, Hardeman County, TX

The radar

The Altus AFB radar (KFDR), 87 km from the middle of the area, began a volume at 22:01 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	Remark
Aug 19, 5:10 PM CDT	TSTM WND GST 81	3 Wnw Gould, OK
Aug 19, 5:25 PM CDT	TSTM WND GST 65	3 Wnw Gould, OK

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

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 12:00Z, 10.0 hours before the alert went out and 180 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: 1123 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 988 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 33 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

491 
WUUS54 KOUN 192159
SVROUN
OKC055-057-TXC197-192230-
/O.NEW.KOUN.SV.W.0458.210819T2159Z-210819T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
459 PM CDT Thu Aug 19 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  Central Harmon County in southwestern Oklahoma...
  Western Greer County in southwestern Oklahoma...
  Northwestern Hardeman County in northern Texas...

* Until 530 PM CDT.

* At 459 PM CDT, severe thunderstorms were located along a line
  extending from 4 miles south of Vinson to 10 miles northeast of
  Kirkland, moving northeast at 10 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Hollis, Gould, Vinson and McKnight. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3457 10000 3490 9992 3503 9964 3451 9982
      3451 9983 3450 9984 3450 9983 3438 10000
TIME...MOT...LOC 2159Z 236DEG 10KT 3484 9983 3453 9998 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

WR

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 19, 7:38 AM CDT	Areal Flood Advisory	OUN	Comanche	36 min
Aug 19, 8:14 AM CDT	Flash Flood Warning	OUN	Comanche	3 hr
Aug 19, 3:27 PM CDT	Special Weather Statement	OUN	Beckham	33 min
Aug 19, 3:29 PM CDT	Special Weather Statement	OUN	Harmon	31 min
Aug 19, 4:10 PM CDT	Special Weather Statement	OUN	Beckham	35 min
Aug 19, 5:14 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OUN	Greer, Harmon, Jackson	31 min
Aug 19, 5:28 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OUN	Greer, Harmon, Jackson	47 min
Aug 19, 6:02 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OUN	Comanche, Jackson, Kiowa, Tillman	28 min
Aug 19, 6:26 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OUN	Jackson, Tillman	34 min
Aug 19, 6:54 PM CDT	Special Weather Statement	OUN	Hardeman	36 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2021 Severe Thunderstorm Warnings in Texas, 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.