Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 155, NWS Norman, OK

April 18, 20154 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 18, 2015, 6:30 PM CDT for 4 counties in 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 18, 2015, 6:30 PM CDT (23:30 UTC)
Expired
Apr 18, 2015, 7:15 PM CDT
In force
45 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

Counties Caddo County, OK, Comanche County, OK, Kiowa County, OK, Washita County, OK

The radar

The Altus AFB radar (KFDR), 76 km from the middle of the area, began a volume at 23:32 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.

IssuedProductOfficeLasted
Apr 18, 2:27 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.5 hours before the alert went out and 121 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, Norman, OK at 12:00Z on 2015-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Norman, OK at 12:00Z on 2015-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1320 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
-8 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 Apr 18, 6:27 PM CDT, 3 minutes earlier.

Area forecast discussion, Apr 18, 6:27 PM CDT, 3 minutes before
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Hazardous weather outlook, Apr 18, 2:55 PM CDT, 3 hours 35 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
255 PM CDT SAT APR 18 2015

OKZ004>048-050>052-TXZ083>090-191800-
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-
255 PM CDT SAT APR 18 2015

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 STORMS ACROSS MUCH OF
OKLAHOMA AND WESTERN NORTH TEXAS.

LOCATION...
THE ENHANCED RISK AREA IS ALONG AND EAST OF A LINE FROM BUFFALO...TO
CHEYENNE...TO MANGUM IN OKLAHOMA...TO QUANAH AND BENJAMIN IN WESTERN
NORTH TEXAS....AND WEST OF A LINE FROM MEDFORD...TO OKLAHOMA CITY..TO
ARDMORE. THE REMAINDER OF OKLAHOMA AND WESTERN NORTH TEXAS IS IN
A SLIGHT RISK.

TIMING...
THROUGH MIDNIGHT.

IMPACTS...
HAIL UP TO THE SIZE OF GOLF BALLS TO TENNIS BALLS...AND WIND
GUSTS UP TO 70 MPH WILL BE THE MAIN CONCERNS. A COUPLE OF
TORNADOES MAY ALSO OCCUR ACROSS MAINLY WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS LATE THIS AFTERNOON AND EVENING.

DISCUSSION...
SCATTERED THUNDERSTORMS HAVE DEVELOPED FROM NORTH CENTRAL INTO WESTERN
OKLAHOMA EARLY THIS AFTERNOON. THESE STORMS HAVE DEVELOPED IN AN
ENVIRONMENT SUPPORTIVE OF RAPID STORM ORGANIZATION...AND HAVE AT TIMES
BECOME SEVERE. THESE STORMS ARE LIKELY TO PERSIST OVER THE NEXT SEVERAL
HOURS...WITH ADDITIONAL STORMS DEVELOPING OVER WESTERN OKLAHOMA DOWN
INTO WESTERN NORTH TEXAS. LARGE HAIL AND DAMAGING WINDS WILL REMAIN
THE MAIN CONCERNS WITH THE STRONGEST STORMS...THOUGH A COUPLE OF
TORNADOES WILL ALSO BE POSSIBLE WITH STORMS ACROSS WESTERN OKLAHOMA
AND WESTERN NORTH TEXAS.

STORMS MAY MERGE INTO ONE OR MORE CLUSTERS THIS EVENING AND TONIGHT...
AS THEY MOVE TO THE NORTHEAST. THESE AREAS OF STORMS MAY CONTINUE TO
POSE A THREAT OF LARGE HAIL AND DAMAGING WINDS...ALONG WITH LOCALLY
HEAVY RAINFALL...AS THEY MOVE THROUGH NORTHERN AND CENTRAL OKLAHOMA.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...

STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
AREA SHOULD PREPARE FOR SEVERE WEATHER OPERATIONS THIS AFTERNOON
THROUGH THIS EVENING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

.THUNDERSTORMS...
SHOWERS AND THUNDERSTORMS WILL LINGER INTO SUNDAY. SEVERE WEATHER
IS UNLIKELY BUT A FEW STORMS MAY BECOME STRONG PRODUCING SMALL
HAIL.

SHOWER AND THUNDERSTORM CHANCES WILL RETURN MONDAY NIGHT THROUGH
FRIDAY...AS A SERIES OF UPPER LEVEL SYSTEMS MOVE ACROSS THE SOUTHERN
PLAINS. STRONG TO SEVERE THUNDERSTORM POTENTIAL WILL LIKELY EXIST
FOR A TIME FROM MID TO LATE NEXT WEEK.

GET GRAPHICS AND MORE DETAILS AT WEATHER.GOV/NORMAN...AND FOLLOW
OUR WEATHER FORECAST OFFICE ON TWITTER AND FACEBOOK.

EM/MBS/AUSTIN

In the hours before

Local storm report, Apr 18, 5:52 PM CDT, 38 minutes before
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Local storm report, Apr 18, 5:56 PM CDT, 34 minutes before
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Special weather statement, Apr 18, 6:03 PM CDT, 27 minutes before
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Local storm report, Apr 18, 6:21 PM CDT, 9 minutes before
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Special weather statement, Apr 18, 6:22 PM CDT, 8 minutes before
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Special weather statement, Apr 18, 6:24 PM CDT, 6 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 18, 12:49 PM CDTSpecial Weather StatementOUNAlfalfa26 min
Apr 18, 1:15 PM CDTSpecial Weather StatementOUNAlfalfa30 min
Apr 18, 1:58 PM CDTSpecial Weather StatementOUNAlfalfa, Major32 min
Apr 18, 2:02 PM CDTSpecial Weather StatementOUNHarper28 min
Apr 18, 2:32 PM CDTSevere Thunderstorm WarningOUNHarper43 min
Apr 18, 2:54 PM CDTSpecial Weather StatementOUNWoods36 min
Apr 18, 3:01 PM CDTSevere Thunderstorm WarningOUNWoods, Woodward44 min
Apr 18, 3:08 PM CDTSpecial Weather StatementOUNMajor37 min
Apr 18, 3:15 PM CDTSpecial Weather StatementOUNCaddo30 min
Apr 18, 3:40 PM CDTSpecial Weather StatementOUNBlaine35 min
Apr 18, 3:45 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Woods45 min
Apr 18, 3:47 PM CDTSpecial Weather StatementOUNMajor28 min
Apr 18, 3:49 PM CDTSevere Thunderstorm WarningOUNBlaine, Kingfisher41 min
Apr 18, 3:54 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Major, Woods51 min
Apr 18, 4:28 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Woods47 min
Apr 18, 4:36 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Tillman39 min
Apr 18, 4:43 PM CDTSpecial Weather StatementOUNEllis32 min
Apr 18, 4:47 PM CDTSevere Thunderstorm WarningOUNAlfalfa43 min
Apr 18, 5:01 PM CDTSpecial Weather StatementOUNBeckham29 min
Apr 18, 5:10 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Jackson, Kiowa, Tillman50 min
Apr 18, 5:13 PM CDTSevere Thunderstorm WarningOUNBeckham, Greer, Roger Mills, Washita47 min
Apr 18, 5:19 PM CDTSpecial Weather StatementOUNGarfield26 min
Apr 18, 5:26 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Grant49 min
Apr 18, 5:36 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Woods39 min
Apr 18, 5:51 PM CDTSevere Thunderstorm WarningOUNCaddo, Comanche, Kiowa, Washita39 min
Apr 18, 6:01 PM CDTSevere Thunderstorm WarningOUNCarter, Jefferson, Love44 min
Apr 18, 6:03 PM CDTSpecial Weather StatementOUNCuster27 min
Apr 18, 6:11 PM CDTSevere Thunderstorm WarningOUNGrant49 min
Apr 18, 6:22 PM CDTSpecial Weather StatementOUNGrady38 min
Apr 18, 6:24 PM CDTSpecial Weather StatementOUNHarper36 min
Apr 18, 6:35 PM CDTSevere Thunderstorm WarningOUNCarter, Garvin, Murray40 min
Apr 18, 6:38 PM CDTSevere Thunderstorm WarningOUNCanadian, Cleveland, Grady, McClain, Oklahoma52 min
Apr 18, 6:44 PM CDTSevere Thunderstorm WarningOUNJackson, Kiowa, Washita31 min
Apr 18, 6:45 PM CDTSevere Thunderstorm WarningOUNHarper20 min
Apr 18, 6:56 PM CDTSevere Thunderstorm WarningOUNCuster, Washita19 min
Apr 18, 6:59 PM CDTSpecial Weather StatementOUNGarvin, McClain31 min
Apr 18, 3:26 PM CDTSevere Thunderstorm WarningOUNArcher, Baylor49 min
Apr 18, 4:10 PM CDTSevere Thunderstorm WarningOUNArcher, Baylor, Wichita, Wilbarger50 min
Apr 18, 6:46 PM CDTSpecial Weather StatementOUNWichita29 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2015Every severe thunderstorm warning in 2015

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.