Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 387, NWS Norman, OK

July 11, 2021Clay County, Wichita County, Texas; 7 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jul 11, 2021, 12:23 AM CDT for Clay County, Wichita County, Texas; 7 counties in Oklahoma. It was in force for 67 min. 1 report 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: Jul 11, 2021, 12:23 AM CDT (05:23 UTC)
Expired: Jul 11, 2021, 1:30 AM CDT
In force: 67 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Carter County, OK, Comanche County, OK, Cotton County, OK, Jefferson County, OK, Love County, OK, Marshall County, OK, Tillman County, OK, Clay County, TX, Wichita County, TX

The radar

The Altus AFB radar (KFDR), 138 km from the middle of the area, began a volume at 05:25 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.

What was reported inside it

Time	Report	Where	Remark
Jul 11, 12:35 AM CDT	TSTM WND GST 65	1 W Ardmore, OK	TREE BLOWN ACROSS THE HIGHWAY.

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

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 12 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The watch it was issued in

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

Issued	Product	Office	Lasted
Jul 10, 9:35 PM CDT	Severe Thunderstorm Watch	SPC	5 hr
Jul 10, 5:29 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 5.4 hours before the alert went out and 131 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: 1457 J/kg
Mixed-layer CIN: -26 J/kg
Mixed-layer LCL: 1695 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -51 m²/s²
0-3 km storm-relative helicity: -26 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

178 
WUUS54 KOUN 110523
SVROUN
OKC019-031-033-067-085-095-141-TXC077-485-110630-
/O.NEW.KOUN.SV.W.0387.210711T0523Z-210711T0630Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
1223 AM CDT Sun Jul 11 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  Southwestern Comanche County in southwestern Oklahoma...
  Jefferson County in southern Oklahoma...
  Love County in southern Oklahoma...
  Cotton County in southwestern Oklahoma...
  Carter County in southern Oklahoma...
  Southwestern Marshall County in southeastern Oklahoma...
  Eastern Tillman County in southwestern Oklahoma...
  Northern Clay County in northern Texas...
  Northeastern Wichita County in northern Texas...

* Until 130 AM CDT.

* At 1223 AM CDT, severe thunderstorms were located along a line
  extending from 5 miles west of Chattanooga to 4 miles northeast of
  Sugden to 6 miles southeast of Milo, moving southeast at 25 mph.

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

  SOURCE...Trained weather spotters estimated 60 mph winds near 
           Comanche.

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

* Locations impacted include...
  Northwestern Wichita Falls, Ardmore, Burkburnett, Marietta,
  Walters, Waurika, Lone Grove, Healdton, Wilson, Dickson,
  Grandfield, Ringling, Temple, Ryan, Springer, Petrolia, Byers,
  Dean, Chattanooga and Thackerville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3376 9719 3385 9717 3392 9721 3382 9743
      3391 9747 3390 9759 3399 9767 3386 9783
      3389 9798 3382 9798 3399 9870 3457 9887
      3425 9795 3429 9756 3435 9756 3438 9717
      3390 9683 3395 9699 3385 9709 3372 9712
TIME...MOT...LOC 0523Z 335DEG 24KT 3441 9875 3411 9792 3427 9726 

HAIL...0.75IN
WIND...60MPH
 
$$

Mahale

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Norman, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 11, 12:21 AM CDT, 2 minutes earlier.

Area forecast discussion, Jul 11, 12:21 AM CDT, 2 minutes before

Area Forecast Discussion
National Weather Service Norman OK
1221 AM CDT Sun Jul 11 2021

...New AVIATION...

.SHORT TERM...
(This evening through Sunday)
Issued at 322 PM CDT Sat Jul 10 2021

Storms are expected to continue to develop across southwest
Missouri, southern Kansas, northeast Oklahoma and eventually
north-central Oklahoma this afternoon.

Storms will continue to develop along and ahead of a cold front that
is moving into northwest Oklahoma this afternoon. Modest instability
and strengthening deep layer sheer will support, storms with
supercellular characteristics, at least initially. These storms will
pose a large hail, damaging wind and at least a very low tornado
risk. However, veered low level flow and more linear forcing along
the surface front will lead to an expected quick transition to a
more linear mode along the boundary. Primary hazard will become
damaging wind gusts and with a secondary heavy rainfall concern as
precipitable water values remain high. However, progressive nature
of this activity is expected to limit the overall heavy rainfall
threat.

HRRR would suggest convection would approach the I-40 corridor 9pm
or a little after. There has been a trend of slowing the southward
progression down in the laster few runs. The storms would then
approach the Red river around 3 or 4 in the morning. Although an
overall downward trend is expected after midnight, some severe risk
does appear possible through the night time hours.

Will keep some lingering precip chances along the Red river Sunday
morning, but most of the activity should be south of the area.
Models are also showing another embedded shortwave rotating around
the upper low to our northeast during the day Sunday. This may
result in a few showers or thunderstorms during the afternoon hours,
mainly along and east of the I-35 corridor. Otherwise, daytime temps
will be a bit lower on Sunday as will the dewpoints as slightly
drier air filters south behind the front.

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 324 PM CDT Sat Jul 10 2021

The front exits the area and winds become light Sunday night and
winds veer to the SE/S by Monday afternoon as the surface ridge
axis moves eastward. The NAM/GFS suggest thunderstorm development
over western north TX and western OK Monday evening into early
Tuesday morning as a LLJ develops atop the retreating cold front,
or weak warm front. Left POPs low for now, but will continue to
watch trends.

The midlevel low pressure system that brought us the cold front
moves slowly across the midwest, before lifting northeast across
the Great Lakes on Tuesday. Meanwhile, the broad upper ridge that
has contributed to record heat across the western CONUS begins to
break down and north flow aloft will likewise weaken over our area.

A wave then translates across the northern plains midweek, and
there are low POPs for precipitation for northern Oklahoma on
Wednesday night into Thursday and again Thursday night into Friday.
The associated frontal boundaries and bulk of precipitation,
however, appears to remain well to our north.

Thompson

&&

.AVIATION...
(06Z TAFS)
Issued at 1158 PM CDT Sat Jul 10 2021

Line of strong to severe thunderstorms continues to move south
across southern OK. They will move out of LAW soon but then into
SPS. VSBYs will drop to near 1SM within very heavy rainfall but
should only last ~1 hr or less. Some brief MVFR cigs will be
possible over northern OK around 15-17Z Sunday. Otherwise, expect
northerly winds behind a cold front thru the early morning hours
and into Sunday with clearing skies throughout the day.

&&

.UPPER AIR...
Issued at 640 PM CDT Sat Jul 10 2021

No upper air flights are planned at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  91  68  85  64 /  20  80   0   0
Hobart OK         95  68  90  65 /  10  70   0  10
Wichita Falls TX  95  73  93  68 /   0  80  10  10
Gage OK           94  65  88  63 /  30   0   0   0
Ponca City OK     89  66  82  62 /  80  50  20  10
Durant OK         93  72  92  67 /   0  80  30  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&

SHORT TERM...30
LONG TERM....01
AVIATION...03

Hazardous weather outlook, Jul 10, 7:14 PM CDT, 5 hours 9 minutes before

Hazardous Weather Outlook...UPDATED
National Weather Service Norman OK
714 PM CDT Sat Jul 10 2021

OKZ004>048-050>052-TXZ083>090-120015-
Harper-Woods-Alfalfa-Grant-Kay-Ellis-Woodward-Major-Garfield-
Noble-Roger Mills-Dewey-Custer-Blaine-Kingfisher-Logan-Payne-
Beckham-Washita-Caddo-Canadian-Oklahoma-Lincoln-Grady-McClain-
Cleveland-Pottawatomie-Seminole-Hughes-Harmon-Greer-Kiowa-Jackson-
Tillman-Comanche-Stephens-Garvin-Murray-Pontotoc-Coal-Cotton-
Jefferson-Carter-Johnston-Atoka-Love-Marshall-Bryan-Hardeman-
Foard-Wilbarger-Wichita-Knox-Baylor-Archer-Clay-
714 PM CDT Sat Jul 10 2021

This hazardous weather outlook is for portions of northern...
western...central...and southern Oklahoma...and western north
Texas.

.DAY ONE...Through Tonight...

.Thunderstorms...
There is an enhanced risk of severe thunderstorms this evening
across portions of central Oklahoma. Additional severe thunderstorms
are also possible across southwestern and southern Oklahoma, and
western north Texas late tonight through early Sunday morning. The
main threats will be wind gusts exceeding 60 mph and hail up to
the size of golf balls. The severe weather threat should end after
3 AM.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...

Storm spotter groups and emergency management personnel across
Oklahoma and north Texas should prepare for severe weather
operations from mid afternoon through early Sunday morning.

.Heavy rainfall...
Localized flooding will be possible through late tonight mainly
across portions of central and south central Oklahoma.

.DAYS TWO THROUGH SEVEN...Sunday through Friday...

.Thunderstorms...
Thunderstorms will remain possible Sunday morning and afternoon
across southern Oklahoma and north Texas, although the severe
weather potential will be low. Isolated storms will be possible
over southeast Oklahoma and north central Texas on Monday. Storms
will again be possible later in the week from Wednesday night
through Friday with the highest chances of storms across northern
and western Oklahoma Thursday night and Friday.

Get graphics and more details at weather.gov/norman...and follow
our weather forecast office on Twitter and Facebook.

In the hours before

Local storm report, Jul 10, 10:56 PM CDT, 1 hour 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1056 PM CDT SAT JUL 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1040 PM     TSTM WND GST     2 SSE CHICKASHA         35.02N 97.93W
07/10/2021  M61 MPH          GRADY              OK   MESONET

&&

RB

Local storm report, Jul 10, 11:16 PM CDT, 1 hour 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1116 PM CDT SAT JUL 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1108 PM     TSTM WND GST     1 NE MEERS              34.80N 98.56W
07/10/2021  M65 MPH          COMANCHE           OK   TRAINED SPOTTER

&&

RB

Local storm report, Jul 10, 11:25 PM CDT, 58 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1125 PM CDT SAT JUL 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1124 PM     TSTM WND GST     1 N ADA                 34.79N 96.66W
07/10/2021  E65 MPH          PONTOTOC           OK   PUBLIC

&&

RB

Special weather statement, Jul 10, 11:35 PM CDT, 48 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1135 PM CDT Sat Jul 10 2021

OKZ027-039>041-046-110500-
Grady OK-Stephens OK-Carter OK-Garvin OK-Murray OK-
1135 PM CDT Sat Jul 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR southeastern Grady...eastern
Stephens...northwestern Carter...western Garvin and west central
Murray Counties Until midnight CDT...

AT 1132 PM CDT, strong thunderstorms were along a line extending from
7 miles south of Bray to 8 miles west of Foster to 5 miles west of
Antioch, moving southeast at 40 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 50 MPH...
Minor flooding in areas of poor drainage...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

&&

LAT...LON 3429 9783 3430 9739 3450 9714 3483 9752
      3463 9797
TIME...MOT...LOC 0432Z 326DEG 34KT 3452 9782 3460 9764 3470 9750

Mahale

Local storm report, Jul 11, 12:05 AM CDT, 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1205 AM CDT SUN JUL 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1154 PM     FLASH FLOOD      2 SW FORT SILL          34.64N 98.43W
07/10/2021                   COMANCHE           OK   TRAINED SPOTTER

            WATER IS 9 INCHES HIGH AND MOVING INTO A
            HOME. VEHICLES STALLED.

&&

RB

Local storm report, Jul 11, 12:09 AM CDT, 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1209 AM CDT SUN JUL 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1200 AM     TSTM WND DMG     2 NW COMANCHE           34.39N 98.00W
07/11/2021                   STEPHENS           OK   TRAINED SPOTTER

            ESTIMATED 60 MPH GUST. TREES BENT OVER.

&&

RB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 11, 12:46 AM CDT	Special Weather Statement	OUN	Hardeman	44 min
Jul 11, 12:48 AM CDT	Severe Thunderstorm Warning	OUN	Hardeman, Wichita, Wilbarger	42 min
Jul 11, 1:24 AM CDT	Areal Flood Advisory	OUN	Wilbarger	3 hr
Jul 11, 1:24 AM CDT	Severe Thunderstorm Warning	OUN	Archer, Baylor, Wichita, Wilbarger	51 min
Jul 11, 1:30 AM CDT	Special Weather Statement	OUN	Clay	30 min
Jul 11, 1:36 AM CDT	Areal Flood Advisory	OUN	Archer, Baylor, Clay, Wichita, Wilbarger	3 hr
Jul 11, 1:53 AM CDT	Severe Thunderstorm Warning	OUN	Archer, Baylor	54 min
Jul 11, 2:03 AM CDT	Special Weather Statement	OUN	Foard	42 min
Jul 11, 2:05 AM CDT	Severe Thunderstorm Warning	OUN	Baylor, Foard, Hardeman, Knox, Wilbarger	55 min
Jul 11, 2:10 AM CDT	Special Weather Statement	OUN	Clay	35 min
Jul 11, 2:58 AM CDT	Severe Thunderstorm Warning	OUN	Baylor, Foard, Knox	62 min
Jul 11, 3:59 AM CDT	Special Weather Statement	OUN	Knox	46 min
Jul 11, 4:08 AM CDT	Severe Thunderstorm Warning	OUN	Knox	52 min
Jul 11, 4:24 AM CDT	Areal Flood Advisory	OUN	Knox	3 hr
Jul 10, 7:12 PM CDT	Severe Thunderstorm Warning	OUN	Logan, Payne	18 min
Jul 10, 7:23 PM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Logan, Payne	52 min
Jul 10, 7:47 PM CDT	Special Weather Statement	OUN	Kingfisher	28 min
Jul 10, 7:52 PM CDT	Areal Flood Advisory	OUN	Lincoln, Logan, Payne	3 hr
Jul 10, 7:58 PM CDT	Severe Thunderstorm Warning	OUN	Kingfisher, Lincoln, Logan, Oklahoma, Payne	47 min
Jul 10, 8:02 PM CDT	Special Weather Statement	OUN	Blaine	43 min
Jul 10, 8:14 PM CDT	Severe Thunderstorm Warning	OUN	Blaine, Canadian, Kingfisher	61 min
Jul 10, 8:25 PM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Logan, Oklahoma, Pottawatomie	50 min
Jul 10, 8:27 PM CDT	Special Weather Statement	OUN	Beckham	48 min
Jul 10, 8:36 PM CDT	Areal Flood Advisory	OUN	Lincoln, Logan, Oklahoma	3 hr
Jul 10, 8:49 PM CDT	Flash Flood Warning	OUN	Lincoln, Payne	101 min
Jul 10, 8:53 PM CDT	Areal Flood Advisory	OUN	Lincoln, Oklahoma, Pottawatomie	3 hr
Jul 10, 8:59 PM CDT	Severe Thunderstorm Warning	OUN	Blaine, Caddo, Canadian, Custer, Grady, Washita	61 min
Jul 10, 9:02 PM CDT	Flash Flood Warning	OUN	Oklahoma	3 hr
Jul 10, 9:11 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Lincoln, McClain, Oklahoma, Pottawatomie	49 min
Jul 10, 9:20 PM CDT	Special Weather Statement	OUN	Okfuskee	40 min
Jul 10, 9:31 PM CDT	Areal Flood Advisory	OUN	Cleveland, McClain, Oklahoma, Pottawatomie, Seminole	3 hr
Jul 10, 9:35 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Cleveland, Grady, McClain	25 min
Jul 10, 9:43 PM CDT	Areal Flood Advisory	OUN	Blaine, Caddo, Canadian, Grady	3 hr
Jul 10, 9:43 PM CDT	Flash Flood Warning	OUN	Oklahoma	2 hr
Jul 10, 10:00 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Grady, Kiowa, Washita	45 min
Jul 10, 10:02 PM CDT	Special Weather Statement	OUN	Cleveland, McClain, Pottawatomie	43 min
Jul 10, 10:19 PM CDT	Areal Flood Advisory	OUN	Seminole	3 hr
Jul 10, 10:23 PM CDT	Areal Flood Advisory	OUN	Caddo, Grady	3 hr
Jul 10, 10:37 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Grady, Kiowa, Washita	38 min
Jul 10, 10:39 PM CDT	Severe Thunderstorm Warning	OUN	Hughes, McClain, Pontotoc, Pottawatomie, Seminole	51 min
Jul 10, 10:45 PM CDT	Special Weather Statement	OUN	Grady	30 min
Jul 10, 10:48 PM CDT	Severe Thunderstorm Warning	OUN	Garvin, Grady	42 min
Jul 10, 10:54 PM CDT	Special Weather Statement	OUN	Grady	36 min
Jul 10, 11:11 PM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Cotton, Grady, Stephens	3 hr
Jul 10, 11:12 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Grady, Kiowa, Stephens	63 min
Jul 10, 11:15 PM CDT	Severe Thunderstorm Warning	OUN	Coal, Hughes, Johnston, Pontotoc	60 min
Jul 10, 11:31 PM CDT	Flash Flood Warning	OUN	Comanche	3 hr
Jul 10, 11:35 PM CDT	Special Weather Statement	OUN	Stephens	25 min
Jul 10, 11:38 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Cotton, Jefferson, Stephens	52 min
Jul 10, 11:44 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Garvin, Murray, Stephens	46 min
Jul 10, 11:59 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Cotton, Kiowa, Tillman	46 min
Jul 11, 12:02 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan, Coal	58 min
Jul 11, 12:23 AM CDT	Areal Flood Advisory	OUN	Comanche, Cotton, Jefferson, Stephens, Tillman	3 hr
Jul 11, 12:32 AM CDT	Areal Flood Advisory	OUN	Coal, Hughes, Pontotoc	3 hr
Jul 11, 12:43 AM CDT	Severe Thunderstorm Warning	OUN	Carter, Johnston, Love, Marshall	47 min
Jul 11, 12:54 AM CDT	Areal Flood Advisory	OUN	Carter, Garvin, Jefferson, Murray, Stephens	3 hr
Jul 11, 1:05 AM CDT	Areal Flood Advisory	OUN	Atoka, Coal, Johnston, Pontotoc	3 hr
Jul 11, 1:33 AM CDT	Special Weather Statement	OUN	Bryan	42 min
Jul 11, 2:23 AM CDT	Areal Flood Warning	OUN	Comanche	3 hr
Jul 11, 12:15 PM CDT	River Flood Advisory	OUN	Comanche, Cotton	34 hr

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.