Alert archive / Oklahoma / Special Weather Statements in 2021

Special Weather Statement, NWS Norman, OK

April 23, 2021Grady County, Oklahoma

NWS Norman, OK issued this special weather statement at Apr 23, 2021, 8:00 PM CDT for Grady County, Oklahoma. It was in force for 30 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: Apr 23, 2021, 8:00 PM CDT (01:00 UTC)
Expired: Apr 23, 2021, 8:30 PM CDT
In force: 30 min
Issued by: NWS Norman, OK

County Grady County, OK

The radar

The Norman radar (KTLX), 90 km from the middle of the area, began a volume at 01:03 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.

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 1.0 hours before the alert went out and 73 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: 486 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 504 m above ground
0-6 km bulk shear: 59 kt
0-1 km storm-relative helicity: 345 m²/s²
0-3 km storm-relative helicity: 408 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 6.8

Open this sounding in Storm Lab

The text

As transmitted.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Apr 23, 6:27 PM CDT, 1 hour 33 minutes earlier.

Area forecast discussion, Apr 23, 6:27 PM CDT, 1 hour 33 minutes before

Area Forecast Discussion
National Weather Service Norman OK
627 PM CDT Fri Apr 23 2021

...New AVIATION, UPPER AIR...

.UPDATE...
Issued at 1032 AM CDT Fri Apr 23 2021

The upper trough is currently tracking across CO/NM and the
surface low continues to develop over the TX panhandle. Low-
level moisture will continue to advect into our area through
this evening. Latest mesoanalysis data shows steep lapse rates in
place and increasing MUCAPE indicates destabilization is
underway over western/southern Oklahoma and north TX. Increased
POPs for 18Z Friday through 06Z Saturday, as CAMS suggest
widespread convection across portions of western north Texas and
southern Oklahoma around mid- day. Some of these storms may be
strong to severe.

The surface low is prog'd to track southeast along the Red River
and strong to severe thunderstorms are likely to develop over
southwest Oklahoma by early evening. CAMS suggest storms will grow
upscale along the front with perhaps a bowing segment as it moves
through south-central Oklahoma later this evening. Very large
hail, damaging winds, and an isolated tornado are possible.

Thompson

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 159 PM CDT Fri Apr 23 2021

The upper trough is currently tracking across CO/NM and the
surface low continues to develop over the TX panhandle. Low-
level moisture will continue to advect into our area through
this evening. Latest mesoanalysis data shows steep lapse rates in
place and increasing MUCAPE indicates destabilization is
underway over western/southern Oklahoma and north TX. Increased
POPs for 18Z Friday through 06Z Saturday, as CAMS suggest
widespread convection across portions of western north Texas and
southern Oklahoma around mid- day. Some of these storms may be
strong to severe.

The surface low is prog'd to track southeast along the Red River
and strong to severe thunderstorms are likely to develop over
southwest Oklahoma by early evening. CAMS suggest storms will grow
upscale along the front with perhaps a bowing segment as it moves
through south-central Oklahoma later this evening. Very large
hail, damaging winds, and an isolated tornado are possible.

Thompson

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 159 PM CDT Fri Apr 23 2021

Gusty winds Saturday morning behind the front will decrease through
the day as the surface ridge quickly builds over the area. The
airmass behind the front will not offer much change in temperatures,
as highs reach near 70 to the mid 70s across southwest OK by
Saturday afternoon. As the surface high slides eastward and upper
ridging builds overhead temperatures will warm further Sunday. Lee
cyclogenesis east of the Rockies will tighten the pressure gradient
over the area during the day, which will lead to a period of gusty
south winds, especially across western OK. This will increase fire
weather concerns on Sunday across extreme western portions of the
area to the west of a dryline, with similar conditions possible
Monday and Tuesday (depending on dryline positioning this may end up
confined to the TX/OK panhandles).

A deep trough approaches by Tuesday, with models continuing to
disagree on timing and amplitude of the trough. Moisture return no
longer looks to be a question as models advertise now agree on a
deeper, slower trough with more meridional flow. There are still so
me timing differences, however, with the GFS faster and further east
with the dryline on Tuesday (central OK) and the ECM slower and
further west (western OK or the TX panhandle). Given such a deep
trough the slower solution seems more likely (and appears to be the
trend in the models the last few days). The slowing of the trough
may linger the severe risk into Wednesday for at least eastern
portions of the area and may also increase the risk for flooding
concerns. Bottom line, the ingredients still appear favorable for
severe weather in our area Tuesday (and perhaps Wednesday as well),
but details still remain unclear on exactly where and when the
greatest threat will occur.

The front should clear the area by Wednesday night, but the upper
trough will linger overhead through the end of the week. This should
keep temperatures cooler than average to end the week with dry
conditions.

Ware

&&

.AVIATION...
(00Z TAFS)
Issued at 618 PM CDT Fri Apr 23 2021

Mostly IFR/MVFR conditions are expected this evening through the
overnight hours. Showers and thunderstorms are expected to impact
all TAF sites this evening and into the overnight. The primary
threats with these thunderstorms are large hail and wind gusts up
to 80 mph. A cold front is expected to move through the area this
evening, with winds shifting back to the the ENE tomorrow at the
end of the period.

&&

.UPPER AIR...
Issued at 618 PM CDT Fri Apr 23 2021

An Upper Air flight is planned for 00Z on 04/24..

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  52  69  48  79 /  90  10   0   0
Hobart OK         49  72  47  85 /  90   0   0   0
Wichita Falls TX  53  73  49  86 /  70   0   0   0
Gage OK           43  71  48  88 /  40   0   0   0
Ponca City OK     51  69  46  78 / 100  10   0   0
Durant OK         55  73  49  80 /  90  10   0   0

&&

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

SHORT TERM...01
LONG TERM....08
AVIATION...13

Hazardous weather outlook, Apr 23, 2:30 PM CDT, 5 hours 30 minutes before

Hazardous Weather Outlook
National Weather Service Norman OK
230 PM CDT Fri Apr 23 2021

OKZ004>048-050>052-TXZ083>090-241930-
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-
230 PM CDT Fri Apr 23 2021

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

.DAY ONE...Today and Tonight...

.Thunderstorms...
Severe thunderstorms are expected this afternoon and evening
across Oklahoma and northern Texas. Severe thunderstorms this
afternoon and evening across western north Texas and southwestern
OK may contain hail up to the size of baseballs, damaging wind
gusts around 70 mph, and an isolated tornado are possible.

During the evening hours, thunderstorms are expected to become
more numerous across central and south central Oklahoma. These
storms will mainly pose a risk of large hail and damaging winds.
As storms move east of Interstate 35 this evening, the hail threat
is expected to decrease some, but damaging winds will still be a
concern.

Heavy rainfall and localized flooding are also a concern,
especially across central and southern OK as several rounds of
storms are expected this evening.

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

.Thunderstorms...
Severe thunderstorms will be possible next Tuesday across most of
the region.

.Fire Weather...
Elevated to Near Critical fire weather conditions are possible
across western Oklahoma and western north Texas Sunday through
Tuesday.

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, Apr 23, 7:16 PM CDT, 44 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
716 PM CDT FRI APR 23 2021

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

0710 PM     HAIL             1 SW HARROLD            34.07N 99.04W
04/23/2021  E2.00 INCH       WILBARGER          TX   PUBLIC

            TWITTER REPORT WITH PICTURE.

&&

JT

Local storm report, Apr 23, 7:17 PM CDT, 43 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
717 PM CDT FRI APR 23 2021

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

0700 PM     HAIL             5 SW HARROLD            34.03N 99.09W
04/23/2021  E2.00 INCH       WILBARGER          TX   PUBLIC

            TWITTER REPORT WITH PICTURE. 1.5 TO 2.0 INCH HAIL.

&&

JT

Local storm report, Apr 23, 7:21 PM CDT, 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
721 PM CDT FRI APR 23 2021

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

0716 PM     HAIL             3 ESE HARROLD           34.06N 98.99W
04/23/2021  E1.00 INCH       WILBARGER          TX   STORM CHASER

            HWY 240 AND FM125 NEAR ELECTRA

&&

JT

Special weather statement, Apr 23, 7:24 PM CDT, 36 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
724 PM CDT Fri Apr 23 2021

OKZ023-038-240100-
Caddo OK-Comanche OK-
724 PM CDT Fri Apr 23 2021

...SIGNIFICANT WEATHER ADVISORY FOR southeastern Caddo and northern
Comanche Counties Until 800 PM CDT...

AT 723 PM CDT, a strong thunderstorm was located over western Fort
Sill, moving northeast at 35 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts over 50 MPH...

LAT...LON 3495 9852 3495 9811 3463 9814 3456 9854
      3472 9869
TIME...MOT...LOC 0023Z 225DEG 29KT 3471 9853

TL

Local storm report, Apr 23, 8:00 PM CDT, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
800 PM CDT FRI APR 23 2021

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

0728 PM     HAIL             ELECTRA                 34.03N 98.92W
04/23/2021  E1.75 INCH       WICHITA            TX   TRAINED SPOTTER

&&

RCB

Special weather statement, Apr 23, 8:00 PM CDT, 0 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
800 PM CDT Fri Apr 23 2021

OKZ023-027-038-240130-
Grady OK-Caddo OK-Comanche OK-
800 PM CDT Fri Apr 23 2021

...SIGNIFICANT WEATHER ADVISORY FOR southern Grady...southeastern
Caddo and northeastern Comanche Counties Until 830 PM CDT...

AT 758 PM CDT, a strong thunderstorm was located 6 miles southeast of
Cyril, moving northeast at 35 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 50 MPH...

Locations impacted include...
Chickasha, Rush Springs, Cyril, Cement, Norge, Agawam, Ninnekah, Acme
and Laverty.

LAT...LON 3470 9808 3479 9819 3489 9823 3511 9799
      3478 9772
TIME...MOT...LOC 0058Z 231DEG 32KT 3484 9812

JP

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 23, 7:06 PM CDT	Severe Thunderstorm Warning	OUN	Harmon, Jackson	39 min
Apr 23, 7:15 PM CDT	Special Weather Statement	OUN	Garfield	30 min
Apr 23, 7:24 PM CDT	Special Weather Statement	OUN	Comanche	36 min
Apr 23, 7:52 PM CDT	Severe Thunderstorm Warning	OUN	Cotton	37 min
Apr 23, 8:04 PM CDT	Special Weather Statement	OUN	Stephens	26 min
Apr 23, 8:18 PM CDT	Severe Thunderstorm Warning	OUN	Cotton, Jefferson	42 min
Apr 23, 8:24 PM CDT	Severe Thunderstorm Warning	OUN	Garvin, Grady, McClain, Stephens	51 min
Apr 23, 8:36 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson, Stephens	39 min
Apr 23, 8:44 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson	31 min
Apr 23, 8:53 PM CDT	Special Weather Statement	OUN	Cleveland, McClain	37 min
Apr 23, 8:59 PM CDT	Special Weather Statement	OUN	Garvin	31 min
Apr 23, 9:02 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson	43 min
Apr 23, 9:12 PM CDT	Severe Thunderstorm Warning	OUN	Carter, Jefferson, Love, Murray, Stephens	48 min
Apr 23, 9:29 PM CDT	Special Weather Statement	OUN	Cleveland, Garvin, Pottawatomie	31 min
Apr 23, 10:00 PM CDT	Special Weather Statement	OUN	Carter, Murray, Pontotoc, Pottawatomie, Seminole	30 min
Apr 23, 10:29 PM CDT	Special Weather Statement	OUN	Coal, Hughes, Johnston, Love, Marshall, Pontotoc and 1 more	31 min
Apr 23, 11:00 PM CDT	Special Weather Statement	OUN	Atoka, Bryan, Coal, Hughes, Marshall, Seminole	30 min
Apr 23, 11:08 PM CDT	Areal Flood Advisory	OUN	Atoka, Bryan	3 hr
Apr 23, 7:01 PM CDT	Severe Thunderstorm Warning	OUN	Wichita, Wilbarger	44 min
Apr 23, 7:32 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Baylor, Wichita, Wilbarger	43 min
Apr 23, 7:44 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Wichita	46 min
Apr 23, 8:14 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Wichita	46 min
Apr 23, 8:33 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Clay, Wichita	42 min
Apr 23, 8:46 PM CDT	Areal Flood Advisory	OUN	Wichita	3 hr
Apr 23, 9:27 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Clay	48 min
Apr 23, 9:44 PM CDT	Severe Thunderstorm Warning	OUN	Clay	46 min

Nearby

Special Weather Statements in Oklahoma, 2021 Every special weather statement 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.