Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 131, NWS Norman, OK

April 21, 2017Blaine County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 21, 2017, 12:15 AM CDT for Blaine County, Oklahoma. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 21, 2017, 12:15 AM CDT (05:15 UTC)
Expired: Apr 21, 2017, 1:00 AM CDT
In force: 45 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

County Blaine County, OK

The radar

The Vance AFB radar (KVNX), 100 km from the middle of the area, began a volume at 05:16 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 watch it was issued in

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

Issued	Product	Office	Lasted
Apr 20, 9:33 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 5.3 hours before the alert went out and 118 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 909 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 121 m²/s²
0-3 km storm-relative helicity: 350 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.6

Open this sounding in Storm Lab

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 Apr 20, 6:47 PM CDT, 5 hours 28 minutes earlier.

Area forecast discussion, Apr 20, 6:47 PM CDT, 5 hours 28 minutes before

Area Forecast Discussion
National Weather Service Norman OK
647 PM CDT Thu Apr 20 2017

.DISCUSSION...
The 00Z aviation discussion follows....

&&

.AVIATION...
A stalled front from near KADH west-southwest to KSPS will move
little through about 21/2100Z. Numerous showers and thunderstorms
are expected to form by 21/0300Z near/north of the front over
western Oklahoma and north Texas. These storms will then expand
and spread east-northeast as the evening/night progresses, with a
few areas of torrential rain and hail. Strong winds will also be
a concern overnight with the stronger storms. The storms will
likely be so widespread tomorrow morning that some of the TAFs
have prevailing storms with TEMPO "no significant weather", which
is the reverse of the normal forecast pattern. As the front gets a
shove from the north late tomorrow afternoon, mainly after
21/2100Z, winds will turn more northerly and increase at most
sites. The showers and storms should move out of central/western
Oklahoma a few hours after the end of this forecast period
(22/0000Z).

The ceiling and visibility forecasts are very low confidence,
because the widespread convection is expected to produce numerous
exceptions to the "rule" in the forecasts. Winds should be close
to the forecasts, except near the stronger storms that will
produce their own temporary wind fields.

CmS
&&

.PREV DISCUSSION... /issued 258 PM CDT Thu Apr 20 2017/

DISCUSSION...
Increased POPS across most of the forecast area (overnight and
Friday morning), especially southwest Oklahoma. Also added a few
counties across southwest Oklahoma, including the cities of
Lawton, Duncan, and Paul Valley to the Flood Watch.

A cold front continues a slow southward push this afternoon,
and is currently located from near Seminole to Pauls Valley to
Duncan and Wichita Falls.  The airmass ahead of the front is
rather warm with dewpoint temperatures in the mid to upper 60s.

A few storms may develop along or just behind the front late
this afternoon/early evening, but storm coverage should be
isolated. If storms can form, severe weather is certainly
possible.

By mid to late evening, scattered to widespread showers and
thunderstorms are expected to develop. The first storms may
form across southwest and west central Oklahoma. Elevated
instability and effective shear will support some rotating storms
which will enhance the risk of large hail. Several rounds of
precipitation may occur, and this may result in flooding and flash
flooding, especially overnight into Friday morning.

On Friday, the cold front is expected to drift northward during
the day in response to an approaching trough. How far north the
front will lift remains uncertain. Regardless, severe weather
chances will remain until the front pushes back southward late
Friday afternoon and night.

Cool and dry weather is expected this weekend with warmer
temperatures returning early next week. Storm chances will
increase again by late next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  55  65  46  60 /  90  90  30  10
Hobart OK         54  71  45  63 /  80  60  10   0
Wichita Falls TX  61  78  48  64 /  50  40  20  10
Gage OK           51  57  41  60 /  80  70  20   0
Ponca City OK     52  56  44  58 /  80  90  60  10
Durant OK         65  78  50  62 /  30  40  70  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch from midnight CDT tonight through Friday evening for
     OKZ007-008-012-013-018>020-023>031-038>040.

TX...None.
&&

23/03/23

Hazardous weather outlook, Apr 20, 11:28 PM CDT, 47 minutes before

Hazardous Weather Outlook...UPDATED
National Weather Service Norman OK
1128 PM CDT Thu Apr 20 2017

OKZ004>048-050>052-TXZ083>090-220430-
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-
1128 PM CDT Thu Apr 20 2017

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

.DAY ONE...Overnight...

.Thunderstorms...
There is a Slight Risk of severe thunderstorms overnight into
Friday morning.

Location...
The Slight Risk covers locations south and west of a line
extending from Arnett to Stillwater to Ada, Oklahoma. The Slight
Risk includes all of western north Texas. A Marginal Risk exists
elsewhere, except for far northern Oklahoma.

Timing...
Severe thunderstorms are expected to continue through the
overnight hours.

Impacts...
Hail up to the size of tennis balls will be the primary threat.
Winds exceeding 60 mph will also be possible.

Discussion...
Scattered to numerous storms will continue to persist through
Friday morning. Some storms will be severe storms, especially in
the slight risk area. Damaging hail and heavy rain will be the
primary hazards.

.Spotter and emergency management statement...
Storm spotter groups and emergency management personnel across
the risk areas should prepare for possible severe weather
operations this evening and overnight.

.Heavy Rainfall...
Thunderstorms may repeatedly develop over the same areas overnight
and lead to excessive rain totals. The main area of concern will
be locations near Oklahoma city, Kingfisher, and Enid, and points
east through late Friday morning.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday...

.Thunderstorms...
Severe storms will remain possible throughout the day on Friday
into Friday evening. An Enhanced Risk of severe storms will exist
for locations south and east of a line extending from Stillwater
and El Reno, to Chickasha Oklahoma, to Henrietta Texas. Damaging
hail and wind gusts will be the primary threats, but there will
also be a low tornado threat mainly across south- central and
southeast parts of Oklahoma.

Thunderstorm chances return next Wednesday, with severe storms
possible.

.Heavy Rainfall...
Significant rainfall totals appear possible through early Friday
evening. At this time, it appears that the heaviest rain will
fall over the northeast half of Oklahoma which could lead to
flooding of low-lying and poor drainage areas.

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

Mahale

In the hours before

Special weather statement, Apr 20, 10:47 PM CDT, 1 hour 28 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1047 PM CDT THU APR 20 2017

OKZ034>036-210430-
Kiowa OK-Greer OK-Jackson OK-
1047 PM CDT THU APR 20 2017

...SIGNIFICANT WEATHER ADVISORY FOR northwestern Kiowa...southeastern
Greer and northeastern Jackson Counties Until 1130 PM CDT...

AT 1043 PM CDT, two strong thunderstorms were located 4 miles
southeast of Granite and one mile south of Hester, moving northeast
at 20 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 40 MPH...
Frequent cloud to ground lightning...

Locations impacted include...
Hobart, Mangum, Granite, Blair, Lone Wolf, Roosevelt, Warren, Hester
and Altus-Lugert Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3512 9920 3512 9905 3484 9887 3472 9945
      3490 9957
TIME...MOT...LOC 0343Z 245DEG 19KT 3490 9934

03

Special weather statement, Apr 20, 11:28 PM CDT, 47 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1128 PM CDT THU APR 20 2017

OKZ014-016-210515-
Roger Mills OK-Custer OK-
1128 PM CDT THU APR 20 2017

...SIGNIFICANT WEATHER ADVISORY FOR east central Roger Mills and
western Custer Counties Until 1215 AM CDT...

AT 1127 PM CDT, a strong thunderstorm was located 5 miles south of
Hammon, moving east at 35 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 40 MPH...
Frequent cloud to ground lightning...

Locations impacted include...
Clinton, Arapaho, Hammon, Butler, Foss Reservoir and Stafford.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3551 9944 3563 9947 3576 9896 3549 9889
TIME...MOT...LOC 0427Z 258DEG 32KT 3556 9936

03

Special weather statement, Apr 20, 11:29 PM CDT, 46 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1129 PM CDT THU APR 20 2017

OKZ022-035-210515-
Kiowa OK-Washita OK-
1129 PM CDT THU APR 20 2017

...SIGNIFICANT WEATHER ADVISORY FOR northern Kiowa and Washita
Counties Until 1215 AM CDT...

AT 1127 PM CDT, a strong thunderstorm was located near Rocky, moving
northeast at 35 MPH.

HAZARDS INCLUDE...
Hail up to the size of nickels...
Wind gusts to 40 MPH...
Frequent cloud to ground lightning...

Locations impacted include...
Hobart, Cordell, Sentinel, Mountain View, Dill City, Corn, Gotebo,
Bessie, Rocky, Colony, Cloud Chief and Cowden.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3546 9908 3546 9862 3512 9862 3501 9884
      3490 9924
TIME...MOT...LOC 0427Z 233DEG 30KT 3517 9899

03

Special weather statement, Apr 20, 11:53 PM CDT, 22 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
1153 PM CDT THU APR 20 2017

OKZ023-024-210530-
Canadian OK-Caddo OK-
1153 PM CDT THU APR 20 2017

...SIGNIFICANT WEATHER ADVISORY FOR western Canadian and northeastern
Caddo Counties Until 1230 AM CDT...

AT 1149 PM CDT, a strong thunderstorm was located over Lookeba,
moving northeast at 35 MPH.

HAZARDS INCLUDE...
Hail up to one-half inch diameter...
Wind gusts to 40 MPH...

Locations impacted include...
El Reno, Hinton, Binger, Calumet, Lookeba and Cedar Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3524 9836 3538 9851 3568 9816 3548 9795
TIME...MOT...LOC 0449Z 229DEG 28KT 3537 9837

03

Local storm report, Apr 21, 12:01 AM CDT, 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1201 AM CDT FRI APR 21 2017

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

1145 PM     HAIL             CORDELL                 35.30N 98.98W
04/20/2017  E1.50 INCH       WASHITA            OK   STORM CHASER

&&

MAHALE

Local storm report, Apr 21, 12:15 AM CDT, 0 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 9:53 PM CDT	Severe Thunderstorm Warning	OUN	Harmon, Jackson	52 min
Apr 20, 10:10 PM CDT	Special Weather Statement	OUN	Greer	50 min
Apr 20, 10:37 PM CDT	Severe Thunderstorm Warning	OUN	Jackson, Tillman	38 min
Apr 20, 10:47 PM CDT	Special Weather Statement	OUN	Kiowa	43 min
Apr 20, 11:08 PM CDT	Severe Thunderstorm Warning	OUN	Jackson, Tillman	67 min
Apr 20, 11:23 PM CDT	Severe Thunderstorm Warning	OUN	Jackson, Kiowa	52 min
Apr 20, 11:28 PM CDT	Special Weather Statement	OUN	Custer	47 min
Apr 20, 11:29 PM CDT	Special Weather Statement	OUN	Washita	46 min
Apr 20, 11:46 PM CDT	Severe Thunderstorm Warning	OUN	Custer, Washita	44 min
Apr 20, 11:53 PM CDT	Special Weather Statement	OUN	Canadian	37 min
Apr 21, 12:00 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Kiowa	45 min
Apr 21, 12:08 AM CDT	Severe Thunderstorm Warning	OUN	Cotton, Tillman	53 min
Apr 21, 12:10 AM CDT	Severe Thunderstorm Warning	OUN	Grant	34 min
Apr 21, 12:17 AM CDT	Special Weather Statement	OUN	Garfield, Noble	43 min
Apr 21, 12:25 AM CDT	Severe Thunderstorm Warning	OUN	Custer	17 min
Apr 21, 12:27 AM CDT	Severe Thunderstorm Warning	OUN	Canadian, Kingfisher	33 min
Apr 21, 12:36 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche	39 min
Apr 21, 1:06 AM CDT	Special Weather Statement	OUN	Logan	24 min
Apr 21, 1:09 AM CDT	Severe Thunderstorm Warning	OUN	Garfield, Kingfisher, Logan, Noble, Payne	28 min
Apr 21, 1:12 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Grady	29 min
Apr 21, 1:13 AM CDT	Special Weather Statement	OUN	Canadian	32 min
Apr 21, 2:12 AM CDT	River Flood Warning	OUN	Pottawatomie, Seminole	24 hr
Apr 21, 2:12 AM CDT	Special Weather Statement	OUN	Oklahoma	33 min
Apr 21, 2:22 AM CDT	Special Weather Statement	OUN	Canadian	23 min
Apr 21, 2:36 AM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Logan, Oklahoma	39 min
Apr 21, 2:50 AM CDT	Special Weather Statement	OUN	Oklahoma	25 min
Apr 21, 3:13 AM CDT	Special Weather Statement	OUN	Lincoln	32 min
Apr 21, 3:15 AM CDT	Special Weather Statement	OUN	Pottawatomie	30 min
Apr 21, 3:30 AM CDT	Special Weather Statement	OUN	Beckham	30 min
Apr 21, 3:32 AM CDT	Special Weather Statement	OUN	Roger Mills	28 min
Apr 21, 3:38 AM CDT	Special Weather Statement	OUN	Lincoln	22 min
Apr 21, 3:47 AM CDT	Severe Thunderstorm Warning	OUN	Beckham, Roger Mills	43 min
Apr 21, 3:49 AM CDT	Severe Thunderstorm Warning	OUN	Custer, Washita	41 min
Apr 21, 3:52 AM CDT	Special Weather Statement	OUN	Seminole	8 min
Apr 21, 4:02 AM CDT	Severe Thunderstorm Warning	OUN	Custer, Washita	43 min
Apr 21, 4:23 AM CDT	Severe Thunderstorm Warning	OUN	Dewey	25 min
Apr 21, 4:27 AM CDT	Severe Thunderstorm Warning	OUN	Custer, Dewey, Roger Mills	24 min
Apr 21, 4:33 AM CDT	Special Weather Statement	OUN	Woods	27 min
Apr 21, 4:38 AM CDT	Special Weather Statement	OUN	Blaine, Caddo	37 min
Apr 21, 4:41 AM CDT	Special Weather Statement	OUN	Custer	34 min
Apr 21, 4:54 AM CDT	Special Weather Statement	OUN	Woods	36 min
Apr 21, 5:03 AM CDT	Special Weather Statement	OUN	Harper	27 min
Apr 21, 5:09 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian, Grady	37 min
Apr 21, 5:11 AM CDT	Severe Thunderstorm Warning	OUN	Ellis, Harper	49 min
Apr 21, 5:12 AM CDT	Special Weather Statement	OUN	Custer	33 min
Apr 21, 5:24 AM CDT	Special Weather Statement	OUN	Grady	36 min
Apr 21, 5:41 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Grady	27 min
Apr 21, 5:50 AM CDT	Special Weather Statement	OUN	Canadian	25 min
Apr 21, 5:52 AM CDT	Severe Thunderstorm Warning	OUN	Ellis, Harper, Woodward	38 min
Apr 21, 6:32 AM CDT	Special Weather Statement	OUN	Woodward	28 min
Apr 21, 6:43 AM CDT	Special Weather Statement	OUN	Oklahoma	32 min
Apr 21, 6:53 AM CDT	Severe Thunderstorm Warning	OUN	Canadian, Oklahoma	15 min
Apr 21, 7:16 AM CDT	Special Weather Statement	OUN	Kingfisher	29 min
Apr 21, 7:21 AM CDT	Special Weather Statement	OUN	Oklahoma	24 min
Apr 21, 7:29 AM CDT	Areal Flood Advisory	OUN	Canadian, Kingfisher, Logan, Oklahoma	3 hr
Apr 21, 7:45 AM CDT	Special Weather Statement	OUN	Logan	30 min
Apr 21, 7:47 AM CDT	Special Weather Statement	OUN	Beckham, Custer, Washita	28 min
Apr 21, 7:51 AM CDT	Special Weather Statement	OUN	Cleveland	24 min
Apr 21, 8:05 AM CDT	Flash Flood Warning	OUN	Canadian, Logan, Oklahoma	4 hr
Apr 21, 8:14 AM CDT	Special Weather Statement	OUN	Washita	31 min
Apr 21, 8:15 AM CDT	Special Weather Statement	OUN	Cleveland	30 min
Apr 21, 8:19 AM CDT	Severe Thunderstorm Warning	OUN	Cleveland, McClain	26 min
Apr 21, 8:35 AM CDT	Areal Flood Advisory	OUN	Blaine, Caddo	3 hr
Apr 21, 8:35 AM CDT	Special Weather Statement	OUN	Pottawatomie	25 min
Apr 21, 8:42 AM CDT	Flash Flood Warning	OUN	Canadian, Kingfisher	3 hr
Apr 21, 8:42 AM CDT	Special Weather Statement	OUN	Canadian	33 min
Apr 21, 8:49 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian, Grady, Kingfisher, Logan, Oklahoma	41 min
Apr 21, 8:57 AM CDT	Special Weather Statement	OUN	Caddo, Comanche, Grady	33 min
Apr 21, 9:04 AM CDT	Special Weather Statement	OUN	Pottawatomie	26 min
Apr 21, 9:16 AM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian, Cleveland, Grady, Logan, McClain and 1 more	59 min
Apr 21, 9:31 AM CDT	Special Weather Statement	OUN	Comanche, Cotton, Stephens	44 min
Apr 21, 9:32 AM CDT	Flash Flood Warning	OUN	Lincoln, Logan, Oklahoma	2 hr
Apr 21, 9:42 AM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Garvin, Grady, Lincoln, McClain, Pontotoc and 2 more	63 min
Apr 21, 10:17 AM CDT	Areal Flood Advisory	OUN	Lincoln, Pottawatomie, Seminole	118 min
Apr 21, 10:43 AM CDT	Special Weather Statement	OUN	Hughes, Pontotoc, Seminole	47 min
Apr 21, 11:05 AM CDT	Severe Thunderstorm Warning	OUN	Coal, Hughes, Pontotoc, Seminole	40 min
Apr 21, 12:01 PM CDT	Areal Flood Warning	OUN	Lincoln, Logan, Oklahoma	3 hr
Apr 21, 12:49 PM CDT	Areal Flood Warning	OUN	Blaine, Caddo, Canadian, Kingfisher, Oklahoma	116 min
Apr 21, 12:57 PM CDT	Flash Flood Warning	OUN	Payne	3 hr
Apr 21, 1:43 PM CDT	Special Weather Statement	OUN	Payne	17 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2017 Every severe thunderstorm warning in 2017

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.