Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 590, NWS Norman, OK

December 17, 20214 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Dec 17, 2021, 5:57 PM CST for 4 counties in Oklahoma. It was in force for 48 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: Dec 17, 2021, 5:57 PM CST (23:57 UTC)
Expired: Dec 17, 2021, 6:45 PM CST
In force: 48 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Coal County, OK, Hughes County, OK, Pontotoc County, OK, Seminole County, OK

The radar

The Norman radar (KTLX), 90 km from the middle of the area, began a volume at 23:57 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

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 nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 12.0 hours before the alert went out and 229 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: 808 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 575 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 300 m²/s²
0-3 km storm-relative helicity: 300 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.3

Open this sounding in Storm Lab

The text

As transmitted.

842 
WUUS54 KOUN 172357
SVROUN
OKC029-063-123-133-180045-
/O.NEW.KOUN.SV.W.0590.211217T2357Z-211218T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
557 PM CST Fri Dec 17 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  North central Coal County in southeastern Oklahoma...
  Southeastern Seminole County in east central Oklahoma...
  Northeastern Pontotoc County in east central Oklahoma...
  Southwestern Hughes County in southeastern Oklahoma...

* Until 645 PM CST.

* At 557 PM CST, a severe thunderstorm was located near Ada, moving
  northeast at 25 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...
  Ada, Byng, Allen, Francis, Sasakwa, Gerty, Atwood and Spaulding. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3465 9668 3480 9679 3506 9636 3480 9618
TIME...MOT...LOC 2357Z 239DEG 21KT 3476 9666 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Zwink

1 follow-up statement

260 
WWUS54 KOUN 180026
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
626 PM CST Fri Dec 17 2021

OKC029-063-123-133-180045-
/O.CON.KOUN.SV.W.0590.000000T0000Z-211218T0045Z/
Coal OK-Seminole OK-Pontotoc OK-Hughes OK-
626 PM CST Fri Dec 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM CST
FOR NORTH CENTRAL COAL...SOUTHEASTERN SEMINOLE...NORTHEASTERN
PONTOTOC AND SOUTHWESTERN HUGHES COUNTIES...

At 626 PM CST, a severe thunderstorm was located 4 miles southwest of
Allen, moving northeast at 25 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...
Allen, Sasakwa, Gerty, Atwood and Spaulding. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3469 9654 3496 9652 3506 9636 3480 9618
TIME...MOT...LOC 0026Z 239DEG 21KT 3485 9648 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Zwink

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 Dec 17, 1:47 PM CST, 4 hours 10 minutes earlier.

Area forecast discussion, Dec 17, 1:47 PM CST, 4 hours 10 minutes before

Area Forecast Discussion
National Weather Service Norman OK
147 PM CST Fri Dec 17 2021

...New LONG TERM...

.SHORT TERM...
(This afternoon through Saturday)
Issued at 1140 AM CST Fri Dec 17 2021

Summary:

An area of showers and storms will continue across the southeast
half of Oklahoma and north Texas, with a slight risk for severe
storms this afternoon/evening in southeast Oklahoma.

A cold front will clear precipitation out tonight and bring in much
cooler temperatures tonight and tomorrow. Overnight lows will drop
below freezing for much of northern and northwest Oklahoma.

Meteorological Analysis:

Warm air advection has brought showers and storms to much of the
southeast half of Oklahoma and north Texas. Surface based
instability will gradually increase across southeast Oklahoma into
this afternoon (rising to 1000-1500 J/Kg) coinciding with effective
bulk shear of 40 to 50 kts. This will support a severe risk across
our far southeast counties (generally, southeast of a line from
Wichita Falls to Pauls Valley to Holdenville). Additionally, PWATs
are anomalously high (1.2 to 1.5 inches; near record). Despite dry
antecedent conditions, training storms could result in a localized
flooding threat.

A cold front will move through later this evening (entering NW OK
around noon, passing through central OK around 7-9pm). As this front
continues to push through the region overnight, precipitation should
clear out from northwest to southeast and colder temperatures will
fill in behind the front. Between cold air advection and some
clearing in the northwest, expect a decent temperature gradient for
overnight lows ranging from the low to mid 20s in far northwest
Oklahoma to the low to mid 30s across central into southwest
Oklahoma to the lower 40s in south central / southeast Oklahoma and
parts of north Texas. Breezy gradient winds of 15 to 25 mph are
expected to develop late overnight into tomorrow morning. OVernight
wind chills will drop into the teens (possibly single digits) across
much of northern and western Oklahoma.

Saturday will be cold (highs in the low 40s to low 50s). Winds will
be breezy in the morning, then diminish through the afternoon as the
pressure gradient relaxes. A small window of overlap between the
breezy morning winds and the afternoon RH minimum may result in some
brief elevated fire weather conditions across western Oklahoma and
western north Texas.

Day

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 141 PM CST Fri Dec 17 2021

As the cooler airmass settles over the southern Plains region,
Saturday night/Sunday morning will probably bring the coldest low
temperatures of the season to much of Oklahoma and north Texas.
Readings are expected to be in the teens and 20s F.

After that, a slow warming trend will follow for the remainder of
the forecast period, though there is some uncertainty about
temperatures toward the end of next week. Medium-range models
could be in better agreement in their placement of major features
then.

An upper-level low is forecast to move east across north Texas and
southern Oklahoma Sunday and Monday. Earlier forecasts included a
possibility of light rain and/or light snow with this system.
Now, it looks like moisture will be insufficient for measurable
precipitation.

CmS
&&

.AVIATION...
(06Z TAFS)
Issued at 1001 PM CST Thu Dec 16 2021

VFR conditions will continue across most of the region overnight
Thursday night into Friday morning. Scattered showers start to
expand from southeastern Oklahoma to the northwest Friday morning,
which will also bring lower ceilings and MVFR conditions across
the region. A cold front will move into the region from Kansas
Friday evening, shifting surface winds to the north and result in
some heavier showers and storms to develop ahead of the cold
front.

&&

.UPPER AIR...
Issued at 251 AM CST Thu Dec 16 2021

An Upper Air flight is not planned for today.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  35  44  21  45 /  30  10   0   0
Hobart OK         34  46  18  47 /  10  10   0   0
Wichita Falls TX  40  49  24  45 /  50  10   0   0
Gage OK           24  43  15  52 /   0   0   0   0
Ponca City OK     29  42  16  45 /   0   0   0   0
Durant OK         43  52  26  47 /  90  30   0   0

&&

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

SHORT TERM...14
LONG TERM....23
AVIATION...14

Hazardous weather outlook, Dec 17, 12:02 PM CST, 5 hours 55 minutes before

Hazardous Weather Outlook
National Weather Service Norman OK
1202 PM CST Fri Dec 17 2021

OKZ004>048-050>052-TXZ083>090-181815-
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-
1202 PM CST Fri Dec 17 2021

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

.DAY ONE...This Afternoon and Tonight...

.Heavy Rainfall...
Very localized flooding may occur in part of southeast Oklahoma
where rain and thunderstorms may train over the same areas later
today and this evening.

.Thunderstorms...
There is a slight risk for severe thunderstorms in southeastern
Oklahoma this afternoon and evening ahead of, then along, a cold
front that will move through this area. Damaging wind is the primary
hazard, and large hail secondary.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday...

.Fire Weather...
Elevated fire weather conditions are expected in western Oklahoma
Saturday and Sunday afternoons.

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, Dec 17, 5:13 PM CST, 44 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
513 PM CST FRI DEC 17 2021

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

0505 PM     TSTM WND GST     1 N RINGLING            34.19N 97.59W
12/17/2021  M60 MPH          JEFFERSON          OK   MESONET

&&

CMS

Special weather statement, Dec 17, 5:22 PM CST, 35 minutes before

Special Weather Statement
National Weather Service Norman OK
522 PM CST Fri Dec 17 2021

OKZ028-029-040-172345-
Cleveland OK-Garvin OK-McClain OK-
522 PM CST Fri Dec 17 2021

...A strong thunderstorm will impact portions of northwestern Garvin,
south central Cleveland and south central McClain Counties through
545 PM CST...

At 522 PM CST, Doppler radar was tracking a strong thunderstorm 7
miles south of Lindsay, moving northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Purcell, Slaughterville, Lindsay, Lexington, Maysville, Wayne,
Rosedale, Erin Springs and Payne.

This includes Interstate 35 between mile markers 79 and 97.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3467 9756 3468 9757 3468 9761 3473 9767
      3476 9767 3509 9738 3490 9715
TIME...MOT...LOC 2322Z 224DEG 34KT 3473 9759

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Zwink

Local storm report, Dec 17, 5:27 PM CST, 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
527 PM CST FRI DEC 17 2021

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

0445 PM     TSTM WND DMG     10 W RINGLING           34.18N 97.77W
12/17/2021                   JEFFERSON          OK   PUBLIC

            AT LEAST 6 POWER POLES DOWN ALONG US 70. TIME ESTIMATED
            FROM RADAR.

&&

CMS

Local storm report, Dec 17, 5:30 PM CST, 27 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
530 PM CST FRI DEC 17 2021

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

0515 PM     HAIL             ALLEN                   34.88N 96.41W
12/17/2021  E1.00 INCH       PONTOTOC           OK   PUBLIC

            JUST EAST OF ALLEN. TIME APPROXIMATE. VIA SOCIAL MEDIA.

&&

CMS

Special weather statement, Dec 17, 5:37 PM CST, 20 minutes before

Special Weather Statement
National Weather Service Norman OK
537 PM CST Fri Dec 17 2021

OKZ045-TXZ090-180000-
Jefferson OK-Clay TX-
537 PM CST Fri Dec 17 2021

...A strong thunderstorm will impact portions of southwestern
Jefferson and northeastern Clay Counties through 600 PM CST...

At 537 PM CST, Doppler radar was tracking a strong thunderstorm 4
miles northeast of Henrietta, moving northeast at 30 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Henrietta, Ryan and Terral.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3389 9825 3415 9786 3394 9774 3393 9776
      3391 9776 3392 9778 3389 9779 3390 9779
      3388 9780 3388 9782 3386 9783 3385 9787
      3389 9798 3380 9798 3375 9818
TIME...MOT...LOC 2337Z 244DEG 28KT 3385 9813

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Zwink

Special weather statement, Dec 17, 5:42 PM CST, 15 minutes before

Special Weather Statement
National Weather Service Norman OK
542 PM CST Fri Dec 17 2021

OKZ032-180015-
Hughes OK-
542 PM CST Fri Dec 17 2021

...A strong thunderstorm will impact portions of central Hughes
County through 615 PM CST...

At 542 PM CST, Doppler radar was tracking a strong thunderstorm near
Atwood, moving northeast at 30 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Calvin, Lamar, Horntown, Atwood and Spaulding.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3509 9606 3506 9607 3505 9609 3499 9609
      3488 9640 3489 9641 3493 9641 3491 9642
      3498 9647 3525 9618 3510 9605
TIME...MOT...LOC 2342Z 234DEG 24KT 3497 9639

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Zwink

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 17, 7:42 AM CST	Special Weather Statement	OUN	Garvin	33 min
Dec 17, 2:47 PM CST	Special Weather Statement	OUN	Garvin	28 min
Dec 17, 3:06 PM CST	Special Weather Statement	OUN	Seminole	24 min
Dec 17, 3:16 PM CST	Special Weather Statement	OUN	Pontotoc	29 min
Dec 17, 3:18 PM CST	Severe Thunderstorm Warning	OUN	Cotton, Jefferson	42 min
Dec 17, 3:28 PM CST	Severe Thunderstorm Warning	OUN	Hughes, Pontotoc, Seminole	47 min
Dec 17, 3:58 PM CST	Severe Thunderstorm Warning	OUN	Jefferson, Stephens	47 min
Dec 17, 4:10 PM CST	Severe Thunderstorm Warning	OUN	Hughes, Pontotoc, Seminole	50 min
Dec 17, 4:22 PM CST	Severe Thunderstorm Warning	OUN	Jefferson, Stephens	23 min
Dec 17, 4:31 PM CST	Special Weather Statement	OUN	Murray	29 min
Dec 17, 4:41 PM CST	Severe Thunderstorm Warning	OUN	Carter, Jefferson	49 min
Dec 17, 5:02 PM CST	Special Weather Statement	OUN	Hughes	28 min
Dec 17, 5:04 PM CST	Special Weather Statement	OUN	Murray	26 min
Dec 17, 5:14 PM CST	Severe Thunderstorm Warning	OUN	Garvin, Murray, Pontotoc	46 min
Dec 17, 5:22 PM CST	Special Weather Statement	OUN	McClain	23 min
Dec 17, 5:27 PM CST	Severe Thunderstorm Warning	OUN	Carter, Murray	48 min
Dec 17, 5:34 PM CST	Severe Thunderstorm Warning	OUN	Cleveland, Garvin, McClain	41 min
Dec 17, 5:37 PM CST	Special Weather Statement	OUN	Jefferson	23 min
Dec 17, 5:42 PM CST	Special Weather Statement	OUN	Hughes	33 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.