Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 383, NWS Norman, OK

July 10, 20214 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jul 10, 2021, 11:38 PM CDT for 4 counties in Oklahoma. It was in force for 52 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 10, 2021, 11:38 PM CDT (04:38 UTC)
Expired: Jul 11, 2021, 12:30 AM CDT
In force: 52 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Comanche County, OK, Cotton County, OK, Jefferson County, OK, Stephens County, OK

The radar

The Altus AFB radar (KFDR), 80 km from the middle of the area, began a volume at 04:38 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, 12:00 AM CDT	TSTM WND DMG	2 Nw Comanche, OK	ESTIMATED 60 MPH GUST. TREES BENT OVER.

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 22 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, 5:29 PM CDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 10, 9:35 PM CDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 4.6 hours before the alert went out and 116 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: 2495 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 1225 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 156 m²/s²
0-3 km storm-relative helicity: 185 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 14.8

Open this sounding in Storm Lab

The text

As transmitted.

674 
WUUS54 KOUN 110438
SVROUN
OKC031-033-067-137-110530-
/O.NEW.KOUN.SV.W.0383.210711T0438Z-210711T0530Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
1138 PM CDT Sat Jul 10 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  Southern Comanche County in southwestern Oklahoma...
  Northern Jefferson County in southern Oklahoma...
  Stephens County in southern Oklahoma...
  Cotton County in southwestern Oklahoma...

* Until 1230 AM CDT.

* At 1137 PM CDT, severe thunderstorms were located along a line
  extending from 5 miles south of Cache to 9 miles east of Geronimo
  to 3 miles northwest of Duncan, moving southeast at 35 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...
  Lawton, Duncan, Marlow, Walters, Waurika, Cache, Comanche,
  Geronimo, Temple, Hastings, Faxon, Loco, Addington, Cookietown,
  Waurika Lake, Corum, southern Fort Sill, Central High, Empire City
  and Hulen.

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 3422 9849 3467 9875 3468 9795 3428 9756
      3427 9756 3413 9793
TIME...MOT...LOC 0437Z 324DEG 29KT 3454 9861 3447 9821 3456 9800 

HAIL...1.00IN
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 10, 6:52 PM CDT, 4 hours 46 minutes earlier.

Area forecast discussion, Jul 10, 6:52 PM CDT, 4 hours 46 minutes before

Area Forecast Discussion
National Weather Service Norman OK
652 PM CDT Sat Jul 10 2021

...New AVIATION, UPPER AIR...

.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...
(00Z TAFS)
Issued at 640 PM CDT Sat Jul 10 2021

Showers and thunderstorms are expected to increase along a cold
front currently moving across northern Oklahoma. Although
expecting ceilings with the CBs to lower just above MVFR,
reduced visibilities during heavy rain may produce brief periods
of MVFR to IFR conditions. Otherwise away from the CBs, conditions
should stay VFR. Winds behind the cold front will shift and
become northerly. However, outflow boundaries produced from storms
may result in more variable directional surface winds.

&&

.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  68  85  64  87 /  80   0   0  10
Hobart OK         68  90  65  90 /  50   0  10  10
Wichita Falls TX  73  93  68  92 /  70  10  10  10
Gage OK           65  88  63  91 /   0   0   0   0
Ponca City OK     66  82  62  86 /  50  20  10   0
Durant OK         72  92  67  91 /  90  30  10  20

&&

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

SHORT TERM...30
LONG TERM....01
AVIATION...68

Hazardous weather outlook, Jul 10, 7:14 PM CDT, 4 hours 24 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, 10:53 PM CDT, 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1053 PM CDT SAT JUL 10 2021

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

1038 PM     TSTM WND DMG     3 SE BLANCHARD          35.11N 97.63W
07/10/2021                   MCCLAIN            OK   BROADCAST MEDIA

            4 INCH DIAMETER TREE BLOCKING THE ROAD.

&&

RB

Special weather statement, Jul 10, 10:54 PM CDT, 44 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1054 PM CDT Sat Jul 10 2021

OKZ027-110430-
Grady OK-
1054 PM CDT Sat Jul 10 2021

...SIGNIFICANT WEATHER ADVISORY FOR central Grady County Until 1130
PM CDT...

AT 1053 PM CDT, a strong thunderstorm was located near Pocasset,
moving southeast at 25 MPH.

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

Locations impacted include...
Chickasha, Alex, Amber, Pocasset, Tabler and Ninnekah.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Storm intensity is increasing and severe weather may develop rapidly.
Stay alert and listen for warnings.

&&

LAT...LON 3485 9793 3520 9807 3526 9792 3501 9767
      3498 9767
TIME...MOT...LOC 0353Z 329DEG 23KT 3517 9797

Mahale

Local storm report, Jul 10, 10:56 PM CDT, 42 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, 22 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, 13 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, 3 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

The office that day

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

Issued	Product	Office	Counties	Lasted
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, 11:44 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, 12:23 AM CDT	Severe Thunderstorm Warning	OUN	Carter, Comanche, Cotton, Jefferson, Love, Marshall and 1 more	67 min
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, 12:46 AM CDT	Special Weather Statement	OUN	Jackson, Tillman	44 min
Jul 11, 12:48 AM CDT	Severe Thunderstorm Warning	OUN	Jackson, Kiowa, Tillman	42 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, 1:24 AM CDT	Areal Flood Advisory	OUN	Comanche, Jackson, Kiowa, Tillman	3 hr
Jul 11, 1:24 AM CDT	Severe Thunderstorm Warning	OUN	Tillman	51 min
Jul 11, 1:33 AM CDT	Special Weather Statement	OUN	Bryan	42 min
Jul 11, 1:36 AM CDT	Areal Flood Advisory	OUN	Cotton, Jefferson, Tillman	3 hr
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 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.