Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 635, NWS Norman, OK

August 10, 2020Harper County, Woods County, Woodward County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Aug 10, 2020, 6:45 PM CDT for Harper County, Woods County, Woodward County, Oklahoma. It was in force for 40 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: Aug 10, 2020, 6:45 PM CDT (23:45 UTC)
Expired: Aug 10, 2020, 7:25 PM CDT
In force: 40 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Harper County, OK, Woods County, OK, Woodward County, OK

The radar

The Vance AFB radar (KVNX), 102 km from the middle of the area, began a volume at 23:47 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

Dodge City, (KDDC), launched 12:00Z, 11.8 hours before the alert went out and 136 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: 514 J/kg
Mixed-layer CIN: -510 J/kg
Mixed-layer LCL: 2012 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 191 m²/s²
0-3 km storm-relative helicity: 181 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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 Aug 10, 6:32 PM CDT, 13 minutes earlier.

Area forecast discussion, Aug 10, 6:32 PM CDT, 13 minutes before

Area Forecast Discussion
National Weather Service Norman OK
632 PM CDT Mon Aug 10 2020

...New AVIATION...

.SHORT TERM...
(This evening through Tuesday)
Issued at 140 PM CDT Mon Aug 10 2020

Isolate showers and thunderstorms will persist across northern
reaches of Oklahoma this afternoon in the hot and very humid
airmass. Aloft, a weak mid-level wave will approach KS and
northern Oklahoma later today and provide more support for
showers/storms this evening and overnight. A dry line over the
western panhandles this afternoon will initiate more storms as it
moves east into the central panhandles by early evening. Some of
these storms are expected to move into western and northern
Oklahoma this evening and continue across at least the north into
early Tuesday. By this time, the upper trough will move across
northern Oklahoma and keep scattered showers and clouds around
east of I-35 into Tuesday afternoon.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 243 PM CDT Mon Aug 10 2020

The upper-level ridge over the desert Southwest will remain the
main feature affecting our weather through the period. After the
upper-level wave from tonight/tomorrow moves off to the southeast,
there is little in the way of disturbances in the flow until at
least the weekend. Around that time, the upper high shifts north
into Utah and vicinity, altering the northwest flow to more
northerly flow across the southern Plains. This will, assuming it
happens, help bring somewhat cooler air into the region this
weekend. It may also bring more widespread chances for rain.

&&

.AVIATION...
(00Z TAFS)
Issued at 624 PM CDT Mon Aug 10 2020

Thunderstorms have erupted near a weak surface boundary near the
Oklahoma/Kansas border, aided by an upper-level wave. As the wave
departs to the southeast, and nighttime cooling commences, the
storms are expected to diminish. However, there is great
uncertainty regarding whether or not (and where) storms may form
on surface outflow boundaries during the night...and into Tuesday
morning. We have included VCTS for KWWR and KPNC this evening, as
storms should be near those airports for another couple of hours
or so, but otherwise have not mentioned TS because of the low
probability. Otherwise, expect mainly south winds and VFR
conditions.

CmS
&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  76  96  75  96 /  20  20  10  10
Hobart OK         75  99  75 100 /  30  10  10   0
Wichita Falls TX  78  99  77 100 /   0  10   0   0
Gage OK           67  98  71 101 /  50  10  20  10
Ponca City OK     73  94  73  93 /  50  30  20  20
Durant OK         77  98  76  98 /  10  10  10  10

&&

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

SHORT TERM...09
LONG TERM....23
AVIATION...23

Hazardous weather outlook, Aug 10, 12:39 PM CDT, 6 hours 6 minutes before

Hazardous Weather Outlook
National Weather Service Norman OK
1239 PM CDT Mon Aug 10 2020

OKZ004>048-050>052-TXZ083>090-111100-
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-
1239 PM CDT Mon Aug 10 2020

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

.DAY ONE...Through Tonight...

.Thunderstorms...
Thunderstorms will be possible late this afternoon this evening,
mainly across northern Oklahoma. Strong to severe storms capable
of damaging wind gusts will be possible.

.DAYS TWO TH

In the hours before

Special weather statement, Aug 10, 4:29 PM CDT, 2 hours 16 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
429 PM CDT Mon Aug 10 2020

OKZ007-008-102200-
Kay OK-Grant OK-
429 PM CDT Mon Aug 10 2020

...SIGNIFICANT WEATHER ADVISORY FOR northwestern Kay and eastern
Grant Counties Until 500 PM CDT...

AT 424 PM CDT, a strong thunderstorm was located 7 miles west of
Braman, moving northeast at 15 MPH.

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

Locations impacted include...
Braman and Blackwell Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3691 9724 3686 9749 3694 9755 3700 9741
      3700 9724
TIME...MOT...LOC 2124Z 239DEG 13KT 3693 9747

Mahale

Special weather statement, Aug 10, 5:03 PM CDT, 1 hour 42 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
503 PM CDT Mon Aug 10 2020

OKZ004-102230-
Harper OK-
503 PM CDT Mon Aug 10 2020

...SIGNIFICANT WEATHER ADVISORY FOR northwestern Harper County Until
530 PM CDT...

AT 500 PM CDT, a strong thunderstorm was located 6 miles southeast of
Englewood, moving east at 5 MPH.

HAZARDS INCLUDE...
Hail up to one-half inch diameter...
Wind gusts to 50 MPH...
Flooding in areas of poor drainage...

This storm will remain over mainly rural areas of northwestern Harper
County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3700 9976 3691 9975 3689 9995 3697 10000
      3700 10000
TIME...MOT...LOC 2200Z 249DEG 3KT 3697 9992

Mahale

Special weather statement, Aug 10, 5:05 PM CDT, 1 hour 40 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
505 PM CDT Mon Aug 10 2020

OKZ006-102230-
Alfalfa OK-
505 PM CDT Mon Aug 10 2020

...SIGNIFICANT WEATHER ADVISORY FOR northeastern Alfalfa County Until
530 PM CDT...

AT 500 PM CDT, a strong thunderstorm was located near Amorita, moving
northeast at 15 MPH.

HAZARDS INCLUDE...
Hail up to one-half inch diameter...
Wind gusts to 50 MPH...

Locations impacted include...
Amorita, Byron and Waldron.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3700 9811 3690 9811 3687 9832 3694 9839
      3700 9834
TIME...MOT...LOC 2200Z 240DEG 15KT 3695 9828

Mahale

Special weather statement, Aug 10, 6:08 PM CDT, 37 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
608 PM CDT Mon Aug 10 2020

OKZ008-102330-
Kay OK-
608 PM CDT Mon Aug 10 2020

...SIGNIFICANT WEATHER ADVISORY FOR northeastern Kay County Until 630
PM CDT...

AT 604 PM CDT, strong thunderstorms were along a line extending from
5 miles northwest of Grainola to 5 miles southwest of Kaw City,
moving east at 20 MPH.

HAZARDS INCLUDE...
Hail up to one-half inch diameter...
Wind gusts to 50 MPH...

Locations impacted include...
Kaw City and Kaw Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3678 9675 3678 9679 3677 9679 3677 9682
      3675 9682 3674 9683 3675 9687 3675 9689
      3668 9693 3669 9701 3670 9701 3700 9676
      3700 9675
TIME...MOT...LOC 2304Z 261DEG 16KT 3700 9670 3672 9693

Mahale

Special weather statement, Aug 10, 6:13 PM CDT, 32 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
613 PM CDT Mon Aug 10 2020

OKZ004-005-102330-
Harper OK-Woods OK-
613 PM CDT Mon Aug 10 2020

...SIGNIFICANT WEATHER ADVISORY FOR northeastern Harper and
northwestern Woods Counties Until 630 PM CDT...

AT 609 PM CDT, a strong thunderstorm was located 5 miles northeast of
Selman, moving east at 5 MPH.

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

This storm will remain over mainly rural areas of northeastern Harper
and northwestern Woods Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3680 9948 3692 9946 3695 9928 3672 9930
TIME...MOT...LOC 2309Z 276DEG 3KT 3685 9940

Mahale

Special weather statement, Aug 10, 6:30 PM CDT, 15 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
Aug 10, 7:37 AM CDT	Special Weather Statement	OUN	Woods	23 min
Aug 10, 3:41 PM CDT	Special Weather Statement	OUN	Harper	34 min
Aug 10, 4:05 PM CDT	Special Weather Statement	OUN	Alfalfa	25 min
Aug 10, 4:09 PM CDT	Special Weather Statement	OUN	Harper	36 min
Aug 10, 4:20 PM CDT	Severe Thunderstorm Warning	OUN	Harper	40 min
Aug 10, 4:29 PM CDT	Special Weather Statement	OUN	Kay	31 min
Aug 10, 4:35 PM CDT	Severe Thunderstorm Warning	OUN	Grant, Kay	25 min
Aug 10, 4:42 PM CDT	Areal Flood Advisory	OUN	Harper	3 hr
Aug 10, 5:00 PM CDT	Severe Thunderstorm Warning	OUN	Harper	45 min
Aug 10, 5:03 PM CDT	Special Weather Statement	OUN	Harper	27 min
Aug 10, 5:05 PM CDT	Special Weather Statement	OUN	Alfalfa	25 min
Aug 10, 5:08 PM CDT	Severe Thunderstorm Warning	OUN	Harper	67 min
Aug 10, 5:15 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa	42 min
Aug 10, 5:20 PM CDT	Severe Thunderstorm Warning	OUN	Harper, Woods	55 min
Aug 10, 5:43 PM CDT	Flash Flood Warning	OUN	Harper	3 hr
Aug 10, 5:46 PM CDT	Areal Flood Advisory	OUN	Harper, Woods	3 hr
Aug 10, 5:55 PM CDT	Severe Thunderstorm Warning	OUN	Harper	65 min
Aug 10, 6:08 PM CDT	Special Weather Statement	OUN	Kay	22 min
Aug 10, 6:13 PM CDT	Special Weather Statement	OUN	Harper	17 min
Aug 10, 6:16 PM CDT	Flash Flood Warning	OUN	Harper, Woods	3 hr
Aug 10, 6:30 PM CDT	Special Weather Statement	OUN	Harper	45 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2020 Every severe thunderstorm warning in 2020

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.