Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 529, NWS Norman, OK

August 18, 2011Kay County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Aug 18, 2011, 6:40 PM CDT for Kay County, Oklahoma. It was in force for 33 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, 2011, 6:40 PM CDT (23:40 UTC)
Expired
Aug 18, 2011, 7:13 PM CDT
In force
33 min
Issued by
NWS Norman, OK
Area
Storm-based polygon

County Kay County, OK

The radar

The Vance AFB radar (KVNX), 88 km from the middle of the area, began a volume at 23:41 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

Lamont, OK (KLMN), launched 12:00Z, 11.7 hours before the alert went out and 37 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, Lamont, OK at 12:00Z on 2011-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 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, Lamont, OK at 12:00Z on 2011-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 95 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
26 J/kg
Mixed-layer CIN
-405 J/kg
Mixed-layer LCL
1967 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
95 m²/s²
0-3 km storm-relative helicity
201 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 18, 6:25 PM CDT, 15 minutes earlier.

Area forecast discussion, Aug 18, 6:25 PM CDT, 15 minutes before
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Hazardous weather outlook, Aug 18, 11:48 AM CDT, 6 hours 52 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1148 AM CDT THU AUG 18 2011

OKZ004>048-050>052-TXZ083>090-191000-
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-
1148 AM CDT THU AUG 18 2011

THIS HAZARDOUS WEATHER OUTLOOK COVERS NORTHERN...WESTERN...
CENTRAL...AND SOUTHERN OKLAHOMA...AND WESTERN NORTH TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

THUNDERSTORM OUTLOOK...
ISOLATED THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON.

DISCUSSION...
STRONG HEATING WILL LIKELY REMOVE ANY CAP THAT REMAINS THIS
AFTERNOON... EXCEPT POSSIBLY IN SOUTHEAST OKLAHOMA WHERE CLOUD COVER
PERSISTS. NO OBVIOUS FORCING MECHANISMS CAN BE PINPOINTED... BUT
ISOLATED THUNDERSTORM DEVELOPMENT MAY STILL OCCUR. INSTABILITY AND
SHEAR ARE BOTH WEAK... WITH THUNDERSTORMS EXPECTED TO BE
SHORT-LIVED. GIVEN THE VERY HOT AND DRY AIR BELOW CLOUD BASE... ANY
SHOWER OR THUNDERSTORM COULD PRODUCE STRONG WIND GUSTS.
THUNDERSTORMS SHOULD SUBSIDE FOLLOWING SUNSET.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT FRIDAY AUG 19.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...40 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...20 PERCENT.

OTHER HAZARDOUS WEATHER...
HOT TEMPERATURES... DRY VEGETATION... AND BREEZY SOUTHWEST WINDS
WILL COMBINE TO KEEP WILDFIRE POTENTIAL VERY HIGH THIS AFTERNOON.
ADDITIONALLY... HOT TEMPERATURES WILL MAKE OUTDOOR ACTIVITIES
DIFFICULT THIS AFTERNOON. A HEAT ADVISORY IS IN EFFECT.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...

THUNDERSTORM OUTLOOK...
NO MORE THAN ISOLATED THUNDERSTORM COVERAGE IS EXPECTED AFTER THE
WEEKEND.

OTHER HAZARDOUS WEATHER...
TEMPERATURES WILL BE VERY HOT FRIDAY AND SATURDAY...AND THE
PERSISTENT HEAT WILL BE A CONCERN. PLEASE SEE THE HEAT ADVISORY FOR
DETAILS. ALSO DURING THIS TIME...BREEZY SOUTH WINDS WILL KEEP
WILDFIRE POTENTIAL VERY HIGH.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 5 AM
FRIDAY.

In the hours before

Special weather statement, Aug 18, 3:53 PM CDT, 2 hours 47 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
353 PM CDT THU AUG 18 2011

OKZ011-012-182130-
GARFIELD OK-MAJOR OK-
353 PM CDT THU AUG 18 2011

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR GARFIELD AND MAJOR COUNTIES.

AT 353 PM CDT...A STRONG THUNDERSTORM WAS LOCATED 4 MILES NORTHEAST
OF ISABELLA...MOVING EAST AT 15 MPH. THIS STORM WAS PART OF A GROUP
OF STORMS THAT EXTENDED FROM JUST WEST OF FAIRVIEW TO NEAR DRUMMOND.

HAZARDS INCLUDE...
WIND GUSTS TO 50 MPH...

LAT...LON 3628 9801 3616 9811 3616 9846 3645 9838
      3645 9809

CMS
Special weather statement, Aug 18, 4:41 PM CDT, 1 hour 59 minutes before
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Special weather statement, Aug 18, 5:10 PM CDT, 1 hour 30 minutes before
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Special weather statement, Aug 18, 5:31 PM CDT, 1 hour 9 minutes before
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Special weather statement, Aug 18, 6:22 PM CDT, 18 minutes before
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Special weather statement, Aug 18, 6:32 PM CDT, 8 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 11:05 PM CDTSpecial Weather StatementOUNLogan25 min
Aug 18, 3:53 PM CDTSpecial Weather StatementOUNMajor37 min
Aug 18, 4:05 PM CDTSevere Thunderstorm WarningOUNBlaine, Garfield, Kingfisher, Major30 min
Aug 18, 4:41 PM CDTSpecial Weather StatementOUNGarfield, Kingfisher, Major34 min
Aug 18, 5:10 PM CDTSpecial Weather StatementOUNBlaine35 min
Aug 18, 5:31 PM CDTSpecial Weather StatementOUNGrant29 min
Aug 18, 6:22 PM CDTSpecial Weather StatementOUNGrant38 min
Aug 18, 6:32 PM CDTSpecial Weather StatementOUNKay28 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2011Every severe thunderstorm warning in 2011

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.