Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 232, NWS Norman, OK

April 27, 2009Logan County, Payne County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 27, 2009, 1:07 PM CDT for Logan County, Payne 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 27, 2009, 1:07 PM CDT (18:07 UTC)
Expired
Apr 27, 2009, 1:45 PM CDT
In force
38 min
Issued by
NWS Norman, OK
Area
Storm-based polygon

Counties Logan County, OK, Payne County, OK

The radar

The Norman radar (KTLX), 74 km from the middle of the area, began a volume at 18:09 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 27, 12:47 PM CDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Lamont, OK (KLMN), launched 12:00Z, 6.1 hours before the alert went out and 73 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 2009-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1225 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 2009-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 303 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
1225 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
567 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
303 m²/s²
0-3 km storm-relative helicity
269 m²/s²
Significant tornado parameter
2.1
Supercell composite
11.6

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 27, 12:38 PM CDT, 29 minutes earlier.

Area forecast discussion, Apr 27, 12:38 PM CDT, 29 minutes before
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Hazardous weather outlook, Apr 27, 11:35 AM CDT, 1 hour 32 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1135 AM CDT MON APR 27 2009

OKZ004>048-050>052-TXZ083>090-281000-
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-
1135 AM CDT MON APR 27 2009

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

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

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
OKLAHOMA AND WESTERN NORTH TEXAS.

LOCATION...
THE SLIGHT RISK IS SOUTHEAST OF A LINE EXTENDING FROM MUNDAY AND
SEYMOUR TEXAS...TO LAWTON...YUKON...AND PONCA CITY.

TIMING...
THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE NOON THROUGH
8 PM.

IMPACTS...
DAMAGE TO AUTOMOBILES...TENDER VEGETATION...AND ROOF TOPS FROM LARGE
HAIL TO THE SIZE OF TENNIS BALLS. DAMAGING WIND GUSTS OF 65 MPH ARE
ALSO POSSIBLE.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD BE PREPARED FOR SEVERE WEATHER OPERATIONS THIS
AFTERNOON AND EVENING.

DISCUSSION...
AN UNSTABLE AIRMASS WITH MODERATE WIND SHEAR WILL RESIDE NEAR AND
AHEAD OF A COLD FRONT THAT WILL PASS OVER THE REGION THIS AFTERNOON.
THE SLIGHT RISK AREA COVERS LOCATIONS THAT ARE EXPECTED TO BE NEAR
AND AHEAD OF THE MENTIONED COLD FRONT WHEN THUNDERSTORM INITIATION
IS MOST LIKELY. LARGE HAIL WILL BE THE PRIMARY CONCERN WITH ANY
SEVERE STORMS...ALTHOUGH DAMAGING WIND GUSTS WILL ALSO BE POSSIBLE.
THE FRONT IS EXPECTED TO BE ALIGNED NEAR THE WESTERN EDGE OF THE
SLIGHT RISK AREA EARLY THIS AFTERNOON...AND THEN MOVE TO A LINE
EXTENDING FROM NEAR MCALESTER TO MARIETTA BY EARLY EVENING. DURING
THE AFTERNOON...WHEN INSTABILITY WILL BE MAXIMIZED...THE FRONT WILL
BE MOVING THROUGH AREAS EXTENDING FROM AROUND WICHITA FALLS...TO
DUNCAN AND PAULS VALLEY...TO THE OKLAHOMA CITY METRO...
SEMINOLE...AND STILLWATER. THESE LOCATIONS COULD BE IMPACTED BY THE
MOST SEVERE STORMS WITH THE LARGEST HAIL AND TORRENTIAL RAINFALL.
THE SEVERE WEATHER CONCERNS WILL DIMINISH QUICKLY AFTER THE FRONT
PASSES YOUR AREA.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT TUESDAY APR 28.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...80  PERCENT.

OTHER HAZARDOUS WEATHER...
THE MENTIONED COLD FRONT IS EXPECTED TO STALL OVER NORTHERN TEXAS
TONIGHT. THIS COULD RESULT IN EXCESSIVE RAINFALL AMOUNTS ACROSS THE
RED RIVER VALLEY OF SOUTH-CENTRAL AND SOUTHEAST OKLAHOMA TONIGHT...
WHICH WOULD LEAD TO FLOODING OF LOW-LYING AND POOR DRAINAGE AREAS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

THUNDERSTORM OUTLOOK...
AT LEAST A CHANCE FOR STRONG OR SEVERE STORMS WILL BE SEEN EACH DAY
OVER PARTS OF THE NWS NORMAN COUNTY WARNING AREA INTO THE WEEKEND.

OTHER HAZARDOUS WEATHER...
MULTIPLE ROUNDS OF HEAVY RAINFALL COULD CAUSE FLOODING PROBLEMS.
PERSONS WITH INTERESTS IN LOW-LYING AREAS OR NEAR RIVERS WILL NEED
TO PAY EXTRA ATTENTION TO LATER FORECASTS.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED BY 5 AM
TUESDAY MORNING.

In the hours before

Special weather statement, Apr 27, 12:44 PM CDT, 23 minutes before
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Special weather statement, Apr 27, 12:51 PM CDT, 16 minutes before
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Special weather statement, Apr 27, 12:58 PM CDT, 9 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Apr 26, 7:11 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Grant, Woods64 min
Apr 26, 7:13 PM CDTAreal Flood AdvisoryOUNEllis, Harper, Major, Woods, Woodward4 hr
Apr 26, 7:15 PM CDTSevere Thunderstorm WarningOUNCaddo, Canadian, Washita60 min
Apr 26, 7:16 PM CDTSevere Thunderstorm WarningOUNWoodward59 min
Apr 26, 7:19 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Major, Woods41 min
Apr 26, 7:30 PM CDTSevere Thunderstorm WarningOUNComanche, Jackson, Tillman60 min
Apr 26, 7:44 PM CDTAreal Flood AdvisoryOUNEllis, Harper, Woods, Woodward3 hr
Apr 26, 7:59 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Woods, Woodward61 min
Apr 26, 8:10 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Grant65 min
Apr 26, 8:24 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Tillman66 min
Apr 26, 10:22 PM CDTSevere Thunderstorm WarningOUNComanche, Grady, Stephens38 min
Apr 26, 10:59 PM CDTSevere Thunderstorm WarningOUNGrady23 min
Apr 27, 3:52 AM CDTRiver Flood WarningOUNMajor, Woods, Woodward29 hr
Apr 27, 1:18 PM CDTSevere Thunderstorm WarningOUNNoble27 min
Apr 27, 1:24 PM CDTSevere Thunderstorm WarningOUNPayne51 min
Apr 27, 2:34 PM CDTRiver Flood WarningOUNGrant, Kay42 hr
Apr 26, 7:44 PM CDTSevere Thunderstorm WarningOUNFoard, Hardeman, Wilbarger35 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2009Every severe thunderstorm warning in 2009

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.