Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 191, NWS Norman, OK

April 26, 2015Caddo County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 26, 2015, 8:22 PM CDT for Caddo County, Oklahoma. It was in force for 38 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 26, 2015, 8:22 PM CDT (01:22 UTC)
Expired
Apr 26, 2015, 9:00 PM CDT
In force
38 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
1.25 in
Wind
60.0 mph

County Caddo County, OK

The radar

The Norman radar (KTLX), 101 km from the middle of the area, began a volume at 01:22 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 00:00Z, 1.4 hours before the alert went out and 279 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 00:00Z on 2015-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1199 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 00:00Z on 2015-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 square meters per square second.1939587897Sfc1 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
1199 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
1646 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
248 m²/s²
Significant tornado parameter
0.1
Supercell composite
3.3

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 26, 6:21 PM CDT, 2 hours 1 minute earlier.

Area forecast discussion, Apr 26, 6:21 PM CDT, 2 hours 1 minute before
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Hazardous weather outlook, Apr 26, 3:19 PM CDT, 5 hours 3 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
319 PM CDT SUN APR 26 2015

OKZ004>048-050>052-TXZ083>090-272030-
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-
319 PM CDT SUN APR 26 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 THUNDERSTORMS OVER WESTERN
NORTH TEXAS AND PORTIONS OF SOUTHWEST OKLAHOMA... THERE IS ALSO A
SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MOST OF SOUTHERN
OKLAHOMA.

LOCATION...
THE ENHANCED RISK EXTENDS SOUTH OF A LINE FROM ALTUS TO WAURIKA.

THE SLIGHT RISK INCLUDES ALL AREAS ALONG AND SOUTH OF A LINE FROM
ARNETT... TO NORMAN... TO HOLDENVILLE OKLAHOMA.

TIMING...
NOON TO MIDNIGHT

IMPACTS...
THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING DESTRUCTIVE
HAIL TO THE SIZE OF BASEBALLS AND 60 TO 70 MPH DAMAGING WIND
GUSTS. A FEW TORNADOES WILL ALSO BE POSSIBLE... ESPECIALLY ACROSS
PORTIONS OF NORTHERN TEXAS AND SOUTHWESTERN OKLAHOMA.
ADDITIONALLY... LOCALIZED HEAVY RAINFALL MAY LEAD TO FLASH
FLOODING.

DISCUSSION...
A FRONTAL BOUNDARY HAS STALLED NEAR THE RED RIVER AND A DEEPENING
AREA OF LOW PRESSURE ACROSS WEST TEXAS WILL ALLOW A DRYLINE TO MIX
EASTWARD... FROM SOUTHWESTERN OKLAHOMA INTO CENTRAL TEXAS THROUGH
THE AFTERNOON HOURS. SOUTHEAST WINDS AHEAD OF THE DRYLINE WILL
ALLOW CONTINUAL TRANSPORT OF ABUNDANT LOW LEVEL MOISTURE... WHICH
WILL COMBINE WITH SUFFICIENT HEATING FOR THE PRODUCTION OF
MODERATE INSTABILITY. MEANWHILE... A STRONG UPPER LEVEL STORM
SYSTEM WILL CONTINUE TO MOVE INTO THE UNSTABLE AIRMASS THIS
AFTERNOON... RESULTING IN RAPID THUNDERSTORM DEVELOPMENT ALONG
BOTH THE DRYLINE AND THE STALLED FRONT... WHICH MAY BEGIN A SLOW
RETREAT NORTHWARD LATE IN THE DAY. INITIAL STORMS WILL LIKELY
BECOME SEVERE RAPIDLY. COLD TEMPERATURES ALOFT WILL PROMOTE LARGE
HAIL GROWTH... AND SHEAR WILL SUPPORT HAIL TO THE SIZE OF
BASEBALLS IN THE STRONGEST STORMS. THIS POTENTIAL WILL BE GREATEST
ACROSS NORTHERN TEXAS INTO SOUTHWESTERN AND FAR SOUTHERN
OKLAHOMA. AS AN AREA OF BACKED SURFACE WINDS DEVELOPS DURING THE
LATE AFTERNOON AND EARLY EVENING... LOW LEVEL SHEAR WILL INCREASE
THE CHANCE FOR TORNADO DEVELOPMENT WITHIN THE STRONGEST STORMS
ACROSS PORTIONS OF NORTHERN TEXAS AND POTENTIALLY INTO FAR
SOUTHWESTERN OKLAHOMA.

ONE OR MORE STORM CLUSTERS MAY DEVELOP DURING THE EVENING AND
OVERNIGHT HOURS. WITH ADEQUATE INSTABILITY AND FAVORABLE WIND
PROFILES... SEVERE THUNDERSTORM POTENTIAL IS LIKELY TO LINGER
INTO THE EARLY OVERNIGHT... WITH THE MAIN CONCERN BEING LARGE
HAIL AND STRONG WIND GUSTS. HEAVY RAINFALL WILL LIKELY ACCOMPANY
SOME OF THE STORMS... AND AREAS THAT RECEIVE PROLONGED RAINFALL
WITH SEVERAL ROUNDS OF STORMS WILL LIKELY SEE FLOODING.

.SPOTTER AND EMERGENCY MANAGEMENT STATEMENT...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS
THE RISK AREA SHOULD PREPARE FOR SEVERE WEATHER OPERATIONS THIS
AFTERNOON AND TONIGHT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...

.THUNDERSTORMS...
THE THREAT OF SEVERE STORMS SHOULD DIMINISH BY EARLY MONDAY...
BUT A FEW STRONG STORMS WILL REMAIN POSSIBLE... WITH HAIL AND
GUSTY WINDS THE PRIMARY CONCERNS. RAIN IS LIKELY TO LINGER INTO
AT LEAST TUESDAY MORNING... BEFORE GRADUALLY WINDING DOWN DURING
THE DAY. THE PRIMARY CONCERN MONDAY AND TUESDAY WILL BE THE EVER
INCREASING FLOOD POTENTIAL DUE TO PROLONGED HEAVY RAINFALL. AT
THIS TIME... AREAS OF WEST CENTRAL INTO CENTRAL... AND SOUTHERN
OKLAHOMA... APPEAR TO HAVE THE GREATEST CHANCES FOR FLASH
FLOODING AND POSSIBLY RIVER FLOODING. IF MODELS CONTINUE TO
DEPICT HEAVY RAINFALL IN THESE AREAS...A FLOOD WATCH MAY BECOME
NECESSARY.

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

AUSTIN/KURTZ

In the hours before

Special weather statement, Apr 26, 5:04 PM CDT, 3 hours 18 minutes before
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Special weather statement, Apr 26, 5:22 PM CDT, 3 hours before
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Local storm report, Apr 26, 5:42 PM CDT, 2 hours 40 minutes before
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Special weather statement, Apr 26, 6:04 PM CDT, 2 hours 18 minutes before
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Special weather statement, Apr 26, 6:19 PM CDT, 2 hours 3 minutes before
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Special weather statement, Apr 26, 6:33 PM CDT, 1 hour 49 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 26, 7:26 PM CDTSpecial Weather StatementOUNKiowa34 min
Apr 26, 7:30 PM CDTSpecial Weather StatementOUNCaddo30 min
Apr 26, 7:52 PM CDTSpecial Weather StatementOUNCaddo23 min
Apr 26, 8:07 PM CDTSpecial Weather StatementOUNCaddo53 min
Apr 26, 10:56 PM CDTSpecial Weather StatementOUNCoal49 min
Apr 27, 2:00 AM CDTRiver Flood WarningOUNCuster, Roger Mills40 hr
Apr 27, 9:01 AM CDTSpecial Weather StatementOUNBeckham, Greer, Harmon, Jackson, Tillman59 min
Apr 27, 10:01 AM CDTSpecial Weather StatementOUNCotton, Greer, Jackson, Kiowa, Tillman44 min
Apr 27, 10:57 AM CDTSpecial Weather StatementOUNComanche, Cotton, Kiowa, Washita48 min
Apr 27, 11:49 AM CDTAreal Flood AdvisoryOUNComanche, Cotton, Tillman56 min
Apr 27, 2:10 PM CDTAreal Flood AdvisoryOUNStephens2 hr
Apr 27, 2:30 PM CDTRiver Flood WarningOUNGreer, Jackson41 hr
Apr 26, 7:33 PM CDTSpecial Weather StatementOUNFoard27 min
Apr 27, 3:20 AM CDTSpecial Weather StatementOUNBaylor25 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.