Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 566, NWS Norman, OK

August 18, 2018Carter County, Jefferson County, Stephens County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Aug 18, 2018, 3:44 PM CDT for Carter County, Jefferson County, Stephens County, Oklahoma. It was in force for 34 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 18, 2018, 3:44 PM CDT (20:44 UTC)
Expired
Aug 18, 2018, 4:18 PM CDT
In force
34 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Carter County, OK, Jefferson County, OK, Stephens County, OK

The radar

The Altus AFB radar (KFDR), 121 km from the middle of the area, began a volume at 20:46 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

Fort Worth, TX (KFWD), launched 12:00Z, 8.7 hours before the alert went out and 165 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-pSkew-T log-p diagram, Fort Worth, TX at 12:00Z on 2018-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 452 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 12:00Z on 2018-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
452 J/kg
Mixed-layer CIN
-195 J/kg
Mixed-layer LCL
1585 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
147 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

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 18, 3:09 PM CDT, 35 minutes earlier.

Area forecast discussion, Aug 18, 3:09 PM CDT, 35 minutes before
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Hazardous weather outlook, Aug 18, 12:00 PM CDT, 3 hours 44 minutes before
Hazardous Weather Outlook
National Weather Service Norman OK
1200 PM CDT Sat Aug 18 2018

OKZ004>048-050>052-TXZ083>090-191700-
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-
1200 PM CDT Sat Aug 18 2018

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

.DAY ONE...Through Tonight...

.Thunderstorms...
There is a Marginal Risk of severe thunderstorms tonight.

Location...
Western Oklahoma and far western north Texas.

Timing...
11 PM to 3 AM.

Impacts...
Up to 60 mph winds.
Up to quarter size hail.

Discussion...
A complex of thunderstorms is expected to move into western
Oklahoma late this evening or after midnight Sunday morning and
spread south and southeast during the early morning hours. Some of
these storms will be capable of producing strong winds and hail,
although widespread severe weather is not anticipated. The threat
for severe weather should decrease with eastward extent.

In addition, widely scattered thunderstorms are possible this
afternoon, mainly across southwestern Oklahoma and adjacent areas
of western north Texas. Some strong storms are possible, but
organized severe weather is not expected.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...
Storm spotter groups and emergency management personnel across
western Oklahoma and far western north Texas should prepare for
severe weather operations tonight.

.Heavy Rainfall...
Heavy rainfall from thunderstorms this evening and overnight may
result in areas of localized flooding, especially at locations
that have recently had significant rainfall.

.Heat...
Heat index values of 100 to 105 degrees are expected this
afternoon, primarily across southern Oklahoma and western north
Texas.

.DAYS TWO THROUGH SEVEN...Sunday through Friday...

.Thunderstorms...
Thunderstorms are possible Sunday, especially Sunday morning, and
could linger into Monday morning. A few strong to severe storms
are possible during this period, although widespread or
significant severe weather is unlikely. Thunderstorms will also be
possible Wednesday and Thursday of next week.

.Heavy Rainfall..
Heavy rainfall from thunderstorms Sunday may result in localized
flooding, especially at locations that have recently had
significant rainfall.

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, Aug 18, 1:57 PM CDT, 1 hour 47 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE Norman OK
157 PM CDT SAT AUG 18 2018

OKZ039-044-045-181930-
Cotton OK-Stephens OK-Jefferson OK-
157 PM CDT SAT AUG 18 2018

...SIGNIFICANT WEATHER ADVISORY FOR northeastern Cotton...
southwestern Stephens and northwestern Jefferson Counties Until 230
PM CDT....

AT 155 PM CDT, a strong thunderstorm was located near Walters, moving
east at 35 MPH.

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

LAT...LON 3427 9843 3443 9843 3449 9805 3422 9802
TIME...MOT...LOC 1855Z 266DEG 30KT 3434 9832

..speg.
Local storm report, Aug 18, 2:25 PM CDT, 1 hour 19 minutes before
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Special weather statement, Aug 18, 3:32 PM CDT, 12 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 7:18 PM CDTSevere Thunderstorm WarningOUNGarvin, Murray, Pontotoc42 min
Aug 17, 7:57 PM CDTSevere Thunderstorm WarningOUNCarter, Garvin, Murray, Stephens48 min
Aug 17, 7:59 PM CDTSevere Thunderstorm WarningOUNGarvin, Murray, Pontotoc25 min
Aug 17, 8:12 PM CDTAreal Flood AdvisoryOUNGarvin3 hr
Aug 17, 8:12 PM CDTAreal Flood AdvisoryOUNGarvin3 hr
Aug 17, 8:57 PM CDTSpecial Weather StatementOUNGrady33 min
Aug 18, 1:57 PM CDTSpecial Weather StatementOUNCotton33 min
Aug 18, 2:24 PM CDTSevere Thunderstorm WarningOUNCotton, Jefferson, Stephens51 min
Aug 18, 2:46 PM CDTAreal Flood AdvisoryOUNCotton119 min
Aug 18, 3:00 PM CDTSevere Thunderstorm WarningOUNJefferson, Stephens45 min
Aug 18, 3:32 PM CDTSpecial Weather StatementOUNJefferson13 min
Aug 18, 3:53 PM CDTSpecial Weather StatementOUNStephens37 min
Aug 18, 4:03 PM CDTSpecial Weather StatementOUNLove27 min
Aug 18, 4:22 PM CDTSpecial Weather StatementOUNCarter, Garvin, Love, Murray38 min
Aug 18, 4:51 PM CDTSevere Thunderstorm WarningOUNCarter24 min
Aug 18, 4:56 PM CDTSpecial Weather StatementOUNLove34 min
Aug 18, 5:08 PM CDTSevere Thunderstorm WarningOUNCarter, Johnston, Marshall39 min
Aug 18, 5:30 PM CDTSpecial Weather StatementOUNMarshall30 min
Aug 18, 5:38 PM CDTSevere Thunderstorm WarningOUNLove18 min
Aug 18, 5:42 PM CDTSpecial Weather StatementOUNMarshall33 min
Aug 18, 6:09 PM CDTSpecial Weather StatementOUNMarshall36 min
Aug 18, 4:50 PM CDTSpecial Weather StatementOUNClay25 min
Aug 18, 5:09 PM CDTSpecial Weather StatementOUNClay36 min
Aug 18, 5:21 PM CDTAreal Flood AdvisoryOUNClay3 hr
Aug 18, 5:45 PM CDTSpecial Weather StatementOUNJack30 min
Aug 18, 5:53 PM CDTSevere Thunderstorm WarningOUNClay34 min
Aug 18, 6:24 PM CDTSpecial Weather StatementOUNClay36 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2018Every severe thunderstorm warning in 2018

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.