Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 451, NWS Norman, OK

June 12, 2009Harper County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Jun 12, 2009, 4:58 AM CDT for Harper County, Oklahoma. It was in force for 62 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: Jun 12, 2009, 4:58 AM CDT (09:58 UTC)
Expired: Jun 12, 2009, 6:00 AM CDT
In force: 62 min
Issued by: NWS Norman, OK
Area: Storm-based polygon

County Harper County, OK

The radar

The Dodge City radar (KDDC), 111 km from the middle of the area, began a volume at 09:59 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.

Issued	Product	Office	Lasted
Jun 12, 2:04 AM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Dodge City, (KDDC), launched 00:00Z, 10.0 hours before the alert went out and 111 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 342 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 955 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 100 m²/s²
0-3 km storm-relative helicity: 199 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.4

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 Jun 12, 2:37 AM CDT, 2 hours 21 minutes earlier.

Area forecast discussion, Jun 12, 2:37 AM CDT, 2 hours 21 minutes before

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Hazardous weather outlook, Jun 12, 4:41 AM CDT, 17 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
441 AM CDT FRI JUN 12 2009

OKZ004>048-050>052-TXZ083>090-121700-
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-
441 AM CDT FRI JUN 12 2009

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

.DAY ONE...TODAY AND TONIGHT...

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THROUGH TONIGHT
ACROSS PORTIONS OF NORTHERN OKLAHOMA.

LOCATION...
THE SLIGHT RISK IS NORTH AND EAST OF A LINE FROM BUFFALO...TO
FAIRVIEW...TO GUTHRIE...TO HOLDENVILLE.

TIMING...
THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE THROUGH 2 PM.

IMPACTS...
DAMAGE TO TENDER VEGETATION AND AUTOMOBILES FROM HAIL TO THE SIZE OF
GOLFBALLS.

DAMAGING WIND GUSTS UP TO 70 MPH.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS FROM THIS
MORNING THROUGH EARLY THIS AFTERNOON.

DISCUSSION...
A CLUSTER OF THUNDERSTORMS IN SOUTHWEST KANSAS SUSTAINED BY LIFT
FROM AN APPROACHING UPPER LEVEL STORM SYSTEM WILL AFFECT NORTHERN
OKLAHOMA THIS MORNING. THOUGH STORMS EARLY THIS MORNING HAVE HAD A
HISTORY OF PRODUCING LARGE HAIL...DAMAGING WIND GUSTS ARE EXPECTED
TO BECOME THE PRIMARY THREAT FROM THIS CLUSTER. ANOTHER COMPLEX OF
STORMS IN NORTHWEST KANSAS COULD MAKE IT TO NORTHERN OKLAHOMA BY
LATE MORNING. THIS SECOND COMPLEX MAY WEAKEN AS IT MOVES THROUGH
AREAS OF SOUTHERN KANSAS AFFECTED BY EARLIER STORMS...BUT COULD ALSO
POSE A THREAT OF DAMAGING WIND GUSTS.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT SATURDAY JUN 13.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...40 PERCENT.

OTHER HAZARDOUS WEATHER...
NONE.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY...

THUNDERSTORM OUTLOOK...
A FRONTAL BOUNDARY IS FORECAST TO REMAIN OVER OR NEAR OKLAHOMA AND
NORTH TEXAS THROUGH THE WEEKEND. HIGH PRESSURE BUILDING NORTHWARD
FROM TEXAS WILL HAVE A TENDENCY TO SUPPRESS THUNDERSTORM
DEVELOPMENT. HOWEVER...WITH THE BOUNDARY CLOSE BY...ALONG WITH
PLENTY OF MOISTURE AND MODERATE TO STRONG JET STREAM FLOW...
THUNDERSTORM CHANCES WILL CONTINUE FROM SATURDAY INTO EARLY NEXT
WEEK.

OTHER HAZARDOUS WEATHER...
NONE.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT NOON
TODAY.

In the hours before

Special weather statement, Jun 12, 4:42 AM CDT, 16 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
442 AM CDT FRI JUN 12 2009

OKZ004-121015-
HARPER OK-
442 AM CDT FRI JUN 12 2009

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR HARPER COUNTY.

A LINE OF SEVERE THUNDERSTORMS WAS LOCATED FROM 42 MILES NORTHEAST OF
ROSSTON TO 21 MILES WEST OF ROSSTON AT 442 AM CDT...MOVING EAST
SOUTHEAST AT 25 MPH. LARGE HAIL HAS BEEN REPORTED WITH SOME OF THESE
THUNDERSTORMS.

PEOPLE IN HARPER COUNTY SHOULD MONITOR THE WEATHER SITUATION CLOSELY.
LISTEN FOR WARNINGS AND REMAIN ALERT FOR THREATENING WEATHER
CONDITIONS.

24

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 12, 5:28 AM CDT	Severe Thunderstorm Warning	OUN	Woods	62 min
Jun 12, 5:58 AM CDT	Severe Thunderstorm Warning	OUN	Harper, Woodward	62 min
Jun 12, 6:11 AM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Woods	79 min
Jun 12, 6:54 AM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant, Major, Woods	51 min
Jun 12, 7:27 AM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Garfield, Grant, Kay, Major, Noble	63 min
Jun 12, 8:28 AM CDT	Severe Thunderstorm Warning	OUN	Garfield, Kay, Logan, Noble, Payne	62 min
Jun 12, 9:27 AM CDT	Severe Thunderstorm Warning	OUN	Lincoln, Logan, Payne	63 min
Jun 12, 10:28 AM CDT	Severe Thunderstorm Warning	OUN	Lincoln	23 min
Jun 12, 6:47 PM CDT	Severe Thunderstorm Warning	OUN	Love	38 min
Jun 12, 5:48 PM CDT	Severe Thunderstorm Warning	OUN	Clay	33 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2009 Every 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.