Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 566, NWS Norman, OK

June 30, 2017McClain County, Pontotoc County, Pottawatomie County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jun 30, 2017, 6:30 PM CDT for McClain County, Pontotoc County, Pottawatomie 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 counties it named.

The facts

Issued: Jun 30, 2017, 6:30 PM CDT (23:30 UTC)
Expired: Jun 30, 2017, 7:00 PM CDT
In force: 30 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties McClain County, OK, Pontotoc County, OK, Pottawatomie County, OK

The radar

The Norman radar (KTLX), 45 km from the middle of the area, began a volume at 23:29 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
Jun 30, 3:42 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.5 hours before the alert went out and 43 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: 1766 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 805 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 79 m²/s²
0-3 km storm-relative helicity: 138 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 5.2

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 Jun 30, 2:54 PM CDT, 3 hours 36 minutes earlier.

Area forecast discussion, Jun 30, 2:54 PM CDT, 3 hours 36 minutes before

Area Forecast Discussion
National Weather Service Norman OK
254 PM CDT Fri Jun 30 2017

.DISCUSSION...
Primary focus is in the short term with thunderstorm potential.
Other forecast challenges are or efforts to attempt to identify
periods where precipitation chances are greatest.

Latest visible satellite shows a complicated surface pattern with
several features that will be important to convective initiation
and evolution later today. 1.) Gravity waves/undular bores are
propagating away from the area deep into Texas from overnight
convection, 2.) Mid level feature focused midday convection over
eastern Oklahoma and extended westward into southwest Oklahoma.
Subsidence behind this was evident in the cumulus field over
southeast Oklahoma. The western end of this feature is near Hobart
and Altus. 3.) A remnant (albeit increasingly diffuse) outflow
boundary from overnight convection extends from near the Red River
over south-central Oklahoma west-northwestward into southwest
Oklahoma to near and just west of Lawton. 4.) A cold front
drifting southeastward across northern Oklahoma. The cold front
extended from near Perry to just south of Enid to near Elk City as
of early afternoon.

Some enhanced cumulus has been noted near the remnant outflow
boundary over southwest Oklahoma, but this is in an area that
should experience the least amount of synoptic forcing from the
approaching shortwave trough. Latest moisture channel satellite
imagery loop shows the shortwave trough moving from eastern
Colorado into western Kansas now. Given the fairly compact and
positively tilted nature of this shortwave, forcing for ascent may
be quite modest with weak mid-level height falls across the area
trending more neutral with further southwest extent.

Current thinking is that thunderstorms should form near and ahead
of the front, generally along and north of I-44. Initial
development will be in an environment with around 35 knots of 500
mb flow contributing to effective bulk shear of around 40 knots.
Although low level moisture was somewhat lower earlier owing to
convective overturning from morning MCS, upstream environment is
quite moist with PWAT values in excess of 1.5" and approaching
1.75". Moisture should contribute to moderate to strong
instability with MLCAPE in excess of 2,500 J/kg, and even higher
values further southwest across our Texas counties where diabatic
heating has been more extensive. Initial storms may exhibit at
least transient supercell characteristics and could be capable of
large (potentially significant) hail. Upscale growth will probably
occur throughout the evening and the wind threat will increase
across roughly the southern half of Oklahoma. Damaging winds will
become the primary threat fairly quickly as cold pool strengthens
and upscale growth occurs. Additionally, given the moist
environment and potential for some training of storms at least
initially, heavy rainfall amounts and flooding/flash flooding are
possible. This threat could decrease if cold pool is extensive
enough and storms accelerate southeast.

The forecast beyond tonight is still somewhat uncertain. Mid-level
height rises and no well defined boundary tomorrow should limit
convective development, but there still could be enough
destabilization for isolated storms primarily across southern
Oklahoma and western north Texas.

Convection should develop across the higher terrain of the Rockies
and Sangre De Christo mountains tomorrow evening and move eastward
across the southern/central High Plains and eventually could move
into western Oklahoma. This would be more likely if cold pool
development is fairly extensive. Our environment should be
unstable enough to sustain convection (albeit probably in a
weakened state) into the night. We have increased precipitation
probabilities across the northwest portion of the area. Storms
may linger into early Sunday. Generally low probabilities were
retained into early next week. Over the next couple of days we
will be able to better refine next week's forecast.

BRB

&&

.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK  69  88  71  92 /  60  20  40  30
Hobart OK         69  88  71  95 /  50  10  40  20
Wichita Falls TX  72  89  72  96 /  60  20  20  10
Gage OK           62  85  68  94 /  20  10  50  30
Ponca City OK     65  87  69  89 /  30  10  30  40
Durant OK         72  88  73  92 /  70  30  30  20

&&

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

25/12

Hazardous weather outlook, Jun 30, 3:06 PM CDT, 3 hours 24 minutes before

Hazardous Weather Outlook
National Weather Service Norman OK
306 PM CDT Fri Jun 30 2017

OKZ004>048-050>052-TXZ083>090-012015-
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-
306 PM CDT Fri Jun 30 2017

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

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

.Thunderstorms...
There is an Enhanced Risk of severe thunderstorms this afternoon
and tonight across portions of southern Oklahoma and north Texas.
There is also a Slight Risk north and west of the Enhanced Risk
including central and southwestern Oklahoma and additional
portions of north Texas.

.Location...
The Enhanced Risk is generally east of a line from Archer City
Texas to Snyder Oklahoma, and south of a line from Snyder to
Norman to Holdenville.

The Slight Risk is north and west of the Enhanced Risk, and is
generally east of a line from Knox City Texas to Hollis and Elk
City Oklahoma, and south of a line from Elk City to Clinton to
Okarche to Chandler.

.Timing...
4 PM through 1 AM.

.Impacts...
Winds up to 80 mph.
Golf ball size hail.
Flooding rain will also be a possibility.

.Discussion...
Storms are expected to develop late this afternoon and tonight
near a slow moving cold front and possibly near a lingering
outflow boundary across southern Oklahoma left over the area from
the morning showers and thunderstorms. Some severe storms will be
possible late this afternoon and through the evening with large
hail and damaging winds. Heavy rain that could lead to flooding
will also be a concern tonight.

Showers and thunderstorms will remain possible from midnight to
sunrise, but the severe potential is expected to diminish late
this evening and overnight.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...

Storm spotter groups and emergency management personnel across the
risk areas should prepare for severe weather operations from late
afternoon into part of the overnight hours.

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

.Thunderstorms...
Strong to severe storms will be possible again Saturday and Sunday
across parts of Oklahoma and north Texas. Heavy rain and localized
flooding will be possible again on Saturday. Storm chances will
resume Monday night, and continue through Thursday.

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

In the hours before

Special weather statement, Jun 30, 5:54 PM CDT, 36 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
554 PM CDT FRI JUN 30 2017

OKZ024-025-302330-
Oklahoma OK-Canadian OK-
554 PM CDT FRI JUN 30 2017

...SIGNIFICANT WEATHER ADVISORY FOR western Oklahoma and southeastern
Canadian Counties Until 630 PM CDT...

AT 552 PM CDT, strong thunderstorms were along a line extending from
near Yukon to 3 miles northeast of Union City, moving east at 10 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...

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

&&

LAT...LON 3562 9740 3544 9753 3534 9775 3540 9806
      3563 9781 3568 9763
TIME...MOT...LOC 2252Z 272DEG 9KT 3550 9773 3543 9790

BRB

Special weather statement, Jun 30, 6:02 PM CDT, 28 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
602 PM CDT FRI JUN 30 2017

OKZ023-024-302330-
Canadian OK-Caddo OK-
602 PM CDT FRI JUN 30 2017

...SIGNIFICANT WEATHER ADVISORY FOR central Canadian and northern
Caddo Counties Until 630 PM CDT...

AT 600 PM CDT, strong thunderstorms were along a line extending from
4 miles southeast of Calumet to 5 miles north of Eakly, moving east
at 15 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...

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

&&

LAT...LON 3544 9862 3551 9829 3562 9808 3563 9774
      3538 9803 3538 9809 3535 9810 3524 9840
      3531 9862
TIME...MOT...LOC 2300Z 261DEG 14KT 3555 9807 3538 9855

BRB

Special weather statement, Jun 30, 6:18 PM CDT, 12 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
618 PM CDT FRI JUN 30 2017

OKZ031-302345-
Seminole OK-
618 PM CDT FRI JUN 30 2017

...SIGNIFICANT WEATHER ADVISORY FOR northern Seminole County Until
645 PM CDT...

AT 615 PM CDT, a strong thunderstorm was located 5 miles northeast of
Seminole, moving east at 15 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...

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

&&

LAT...LON 3519 9670 3540 9678 3541 9677 3541 9674
      3543 9672 3541 9672 3539 9665 3540 9660
      3541 9659 3539 9654 3541 9654 3544 9657
      3545 9655 3543 9649 3546 9648 3545 9644
      3512 9644
TIME...MOT...LOC 2315Z 256DEG 14KT 3528 9660

BRB

Local storm report, Jun 30, 6:20 PM CDT, 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
620 PM CDT FRI JUN 30 2017

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

0614 PM     HAIL             APACHE                  34.90N 98.36W
06/30/2017  E1.00 INCH       CADDO              OK   PUBLIC

&&

JP

Local storm report, Jun 30, 6:22 PM CDT, 8 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
622 PM CDT FRI JUN 30 2017

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

0618 PM     HAIL             TRIBBEY                 35.12N 97.05W
06/30/2017  E1.00 INCH       POTTAWATOMIE       OK   EMERGENCY MNGR

&&

JP

Local storm report, Jun 30, 6:25 PM CDT, 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
625 PM CDT FRI JUN 30 2017

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

0601 PM     HAIL             MIDDLEBERG              35.11N 97.74W
06/30/2017  E1.00 INCH       GRADY              OK   PUBLIC

&&

JP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 29, 11:38 PM CDT	Severe Thunderstorm Warning	OUN	Harper	47 min
Jun 30, 12:05 AM CDT	Severe Thunderstorm Warning	OUN	Harper, Woods	55 min
Jun 30, 12:33 AM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant, Woods	42 min
Jun 30, 12:38 AM CDT	Special Weather Statement	OUN	Woods	37 min
Jun 30, 1:04 AM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant, Kay	56 min
Jun 30, 1:18 AM CDT	Special Weather Statement	OUN	Garfield, Major	27 min
Jun 30, 1:20 AM CDT	Special Weather Statement	OUN	Woods	25 min
Jun 30, 1:48 AM CDT	Special Weather Statement	OUN	Garfield, Noble	57 min
Jun 30, 1:52 AM CDT	Severe Thunderstorm Warning	OUN	Garfield, Grant, Kay, Noble	38 min
Jun 30, 2:28 AM CDT	Severe Thunderstorm Warning	OUN	Kay, Noble	32 min
Jun 30, 3:28 AM CDT	Special Weather Statement	OUN	Harper	47 min
Jun 30, 3:45 AM CDT	Severe Thunderstorm Warning	OUN	Woods	34 min
Jun 30, 3:55 AM CDT	Special Weather Statement	OUN	Woods	50 min
Jun 30, 4:15 AM CDT	Special Weather Statement	OUN	Woods	60 min
Jun 30, 4:26 AM CDT	Special Weather Statement	OUN	Payne	49 min
Jun 30, 4:32 AM CDT	Severe Thunderstorm Warning	OUN	Noble, Payne	25 min
Jun 30, 4:53 AM CDT	Severe Thunderstorm Warning	OUN	Garfield, Grant	9 min
Jun 30, 5:09 AM CDT	Special Weather Statement	OUN	Payne	51 min
Jun 30, 5:58 AM CDT	Special Weather Statement	OUN	Payne	47 min
Jun 30, 3:38 PM CDT	Special Weather Statement	OUN	Caddo	37 min
Jun 30, 3:49 PM CDT	Special Weather Statement	OUN	Washita	26 min
Jun 30, 3:57 PM CDT	Severe Thunderstorm Warning	OUN	Kiowa, Washita	33 min
Jun 30, 4:18 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Grady	27 min
Jun 30, 4:29 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Kiowa	46 min
Jun 30, 4:44 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Grady	46 min
Jun 30, 5:07 PM CDT	Special Weather Statement	OUN	Canadian	23 min
Jun 30, 5:14 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Kiowa	46 min
Jun 30, 5:18 PM CDT	Severe Thunderstorm Warning	OUN	Grady	42 min
Jun 30, 5:30 PM CDT	Special Weather Statement	OUN	Canadian	30 min
Jun 30, 5:32 PM CDT	Special Weather Statement	OUN	Caddo	28 min
Jun 30, 5:43 PM CDT	Special Weather Statement	OUN	Kiowa	32 min
Jun 30, 5:50 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche, Kiowa	40 min
Jun 30, 5:52 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Pottawatomie	38 min
Jun 30, 5:54 PM CDT	Special Weather Statement	OUN	Canadian	36 min
Jun 30, 5:58 PM CDT	Severe Thunderstorm Warning	OUN	Garvin, Grady, McClain	47 min
Jun 30, 5:59 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche	31 min
Jun 30, 6:02 PM CDT	Special Weather Statement	OUN	Canadian	28 min
Jun 30, 6:05 PM CDT	Areal Flood Advisory	OUN	Grady	3 hr
Jun 30, 6:18 PM CDT	Special Weather Statement	OUN	Seminole	27 min
Jun 30, 6:28 PM CDT	Severe Thunderstorm Warning	OUN	Comanche	47 min
Jun 30, 6:31 PM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Kiowa	3 hr
Jun 30, 6:32 PM CDT	Special Weather Statement	OUN	Canadian	28 min
Jun 30, 6:33 PM CDT	Special Weather Statement	OUN	Canadian	27 min
Jun 30, 6:38 PM CDT	Areal Flood Advisory	OUN	Canadian	3 hr
Jun 30, 6:40 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Garvin, McClain	35 min
Jun 30, 6:43 PM CDT	Severe Thunderstorm Warning	OUN	Harmon, Jackson	47 min
Jun 30, 6:46 PM CDT	Severe Thunderstorm Warning	OUN	Kiowa	44 min
Jun 30, 5:23 PM CDT	Special Weather Statement	OUN	Knox	37 min
Jun 30, 5:35 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Knox	40 min
Jun 30, 5:56 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Hardeman	49 min
Jun 30, 6:14 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Knox	31 min
Jun 30, 6:45 PM CDT	Severe Thunderstorm Warning	OUN	Knox	45 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.