Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 87, NWS Norman, OK

April 13, 2007Stephens County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 13, 2007, 5:15 PM CDT for Stephens County, 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 13, 2007, 5:15 PM CDT (22:15 UTC)
Expired: Apr 13, 2007, 6:00 PM CDT
In force: 45 min
Issued by: NWS Norman, OK
Area: Counties, with a storm outline in the text

County Stephens County, OK

The radar

The Altus AFB radar (KFDR), 104 km from the middle of the area, began a volume at 22:17 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
Apr 13, 1:59 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Fort Sill, OK (KFSI), launched 12:00Z, 10.3 hours before the alert went out and 53 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1491 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 447 m²/s²
0-3 km storm-relative helicity: 635 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

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 Apr 13, 2:19 PM CDT, 2 hours 56 minutes earlier.

Area forecast discussion, Apr 13, 2:19 PM CDT, 2 hours 56 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
219 PM CDT FRI APR 13 2007

.DISCUSSION...
WIDESPREAD SHOWERS AND THUNDERSTORMS MOVING ACROSS THE AREA THIS
AFTERNOON AND EVENING... WITH SEVERE STORMS BEGINNING TO DEVELOP
NEAR WEST NORTH TEXAS COUNTIES. SEVERE STORMS WILL BE POSSIBLE THRU
THIS EVENING ACROSS PARTS OF WEST NORTH TEXAS AND OKLAHOMA. A WARM
FRONT EXTENDED ACROSS PARTS OF WESTERN NORTH TEXAS COUNTIES FROM A
SFC LOW THAT WAS LOCATED OVER WEST TEXAS EARLY THIS AFTERNOON. THE
WARM FRONT MAY LIFT FURTHER NORTH TO NEAR THE RED RIVER THIS
AFTERNOON/EARLY EVENING AS THE SFC LOW MOVES ALONG THE BOUNDARY. UPR
LOW... CURRENTLY OVR THE SOUTHERN ROCKIES IN NEW MEXICO... WILL MOVE
EAST AND NORTHEAST ACROSS THE SOUTHERN/CENTRAL PLAINS TONIGHT INTO
SATURDAY. COLD AIR WILL MOVE INTO THE SOUTHERN PLAINS TONIGHT INTO
SATURDAY AS THE SFC LOW MOVES EAST. RAIN WILL BEGIN TO CHANGE OVER
TO SNOW THIS EVENING IN EXTREME NORTHWEST OKLAHOMA AS THE COLD AIR
BEGINS TO MOVE INTO THE AREA. AS THE COLD AIR CONTINUES TO MOVE
SOUTH INTO THE REGION... PRECIP MAY MIX OR CHANGE OVER TO SNOW
ACROSS APPROXIMATELY THE NORTHERN HALF OF OKLAHOMA OVERNIGHT. SNOW
ACCUMULATIONS WILL BE POSSIBLE IN PARTS OF NORTHERN OK... WITH THE
HIGHEST ACCUMULATIONS IN NORTHWEST OK. SNOW ACCUMULATIONS ARE TRICKY
TO FORECAST FOR TONIGHT DUE TO THE WARM GROUND AND SNOW LIKELY
FALLING FOR AWHILE WITH SFC TEMPS ABOVE FREEZING. HOWEVER... ONE TO
THREE INCHES WILL BE POSSIBLE IN NORTHWEST OK SO WILL CONT WITH SNOW
ADVISORY FOR TONIGHT.

PRECIP WILL END SATURDAY AS UPR LOW MOVES AWAY FROM REGION. SFC HIGH
WILL BUILD INTO THE REGION SATURDAY. THE SFC HIGH WILL CAUSE WINDS
TO BECOME LIGHT SATURDAY NIGHT/SUNDAY MORNING. WITH THE UPPER SYSTEM
EXITING REGION SKIES WILL ALSO CLEAR SATURDAY NIGHT. WITH CLEARING
SKIES AND LIGHT WINDS... PORTIONS OF OKLAHOMA... APPROX THE NORTHERN
THIRD OF THE STATE... MAY SEE TEMPERATURES AT OR BELOW FREEZING ONCE
AGAIN. WINDS WILL SHIFT BACK TO THE SOUTH SUNDAY AS UPR TROUGH MOVES
ONTO THE WEST COAST CAUSING LEE SURFACE TROUGH TO BEGIN TO DEVELOP.
THUNDERSTORMS WILL BE POSSIBLE AGAIN LATE MONDAY INTO TUESDAY AS
STORM SYSTEM APPROACHES AND MOVES ACROSS THE SOUTHERN PLAINS. REST
OF EXTENDED WILL REMAIN DRY WITH WARMER TEMPERATURES.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  38  52  34  66 /  70  20   0   0
HOBART OK         36  54  34  69 /  40  10   0   0
WICHITA FALLS TX  40  58  38  71 /  30  10   0   0
GAGE OK           31  52  30  68 /  90  20   0   0
PONCA CITY OK     35  49  32  63 / 100  30  10   0
DURANT OK         45  54  37  68 /  80  20  10   0

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...SNOW ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT SATURDAY FOR
     OKZ004>006-009-010.

TX...NONE.
&&

08/25

Hazardous weather outlook, Apr 13, 12:00 PM CDT, 5 hours 15 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORMAN OK
1200 PM CDT FRI APR 13 2007

OKZ004>048-050>052-TXZ083>090-141200-
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-
1200 PM CDT FRI APR 13 2007

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 THIS EVENING
ACROSS PORTIONS OF OKLAHOMA AND WESTERN NORTH TEXAS.

LOCATION...
THE SLIGHT RISK AREA IS SOUTH OF A LINE EXTENDING FROM CHEYENNE...TO
WATONGA...TO CHANDLER IN OKLAHOMA...AND INCLUDES ALL OF WESTERN
NORTH TEXAS.

TIMING...
STRONG TO SEVERE THUNDERSTORMS WILL INCREASE IN NUMBER DURING THE
DAY...WITH THE STRONGEST THUNDERSTORMS DEVELOPING BY MID-AFTERNOON.
THE THUNDERSTORMS WILL FINALLY DIMINISH LATE THIS EVENING.

IMPACTS...
NUMEROUS STORMS THROUGHOUT THE SLIGHT RISK AREA WILL PRODUCE LARGE
HAIL THAT COULD CAUSE MINOR DAMAGE TO AUTOMOBILES...ROOFTOPS...AND
TENDER VEGETATION. ONE OR TWO OF THE STRONGEST STORMS MAY PRODUCE
HAIL LARGER THAN GOLF BALLS...WHICH MAY CAUSE MODERATE
DAMAGE...INCLUDING BROKEN GLASS ON AUTOMOBILES AND BUILDINGS.

STORMS IN TEXAS AND ALONG THE RED RIVER IN OKLAHOMA ARE EXPECTED TO
BE THE STRONGEST AND MAY PRODUCE WIND GUSTS TO 70 MPH. ISOLATED
TORNADOES ARE POSSIBLE...MAINLY OVER WESTERN NORTH TEXAS AND THE RED
RIVER VALLEY OF SOUTHERN OKLAHOMA.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS UNTIL 10 PM.

DISCUSSION...
AN INTENSE UPPER LEVEL JET STREAM WILL REMAIN OVER THE SOUTHERN
PLAINS TODAY...ANCHORED BY A TROUGH THAT WILL MOVE FROM NEAR EL PASO
TEXAS TO NORTHWEST OKLAHOMA BY MIDNIGHT. AT THE SURFACE...A WARM
FRONT LOCATED SOUTH OF THE RED RIVER WILL MOVE SLIGHTLY NORTHWARD
THIS AFTERNOON. A BROAD LOW LEVEL JET WILL CONTINUE TO RAPIDLY BRING
MOIST AND UNSTABLE AIR INTO THE SLIGHT RISK AREA...WHILE THE UPPER
LEVELS PROVIDE LIFT FOR NEARLY CONTINUOUS DEVELOPMENT OF STRONG TO
SEVERE THUNDERSTORMS. THE VAST MAJORITY OF THESE STORMS WILL BE
ELEVATED ABOVE A LAYER OF STABLE COLD AIR NEAR THE SURFACE...MEANING
THE MAIN SEVERE WEATHER THREATS WILL BE LARGE HAIL AND HEAVY RAIN.
WIND SHEAR OVER THE ENTIRE REGION WILL SUPPORT ROTATING UPDRAFTS
WHICH MAY PRODUCE HAIL AROUND GOLFBALL SIZE.

A CHANCE FOR EVEN MORE SIGNIFICANT STORMS MAY DEVELOP FROM
MID-AFTERNOON INTO THE EVENING OVER WESTERN NORTH TEXAS AND THE RED
RIVER VALLEY OF SOUTHERN OKLAHOMA...SOUTH OF A LINE FROM ALTUS TO
DUNCAN TO ATOKA. THIS AREA WILL BE IN CLOSE PROXIMITY TO THE MAIN
WARM FRONT. THIS WILL MAXIMIZE THE AVAILABLE INSTABILITY...AND BRING
STORM BASES CLOSER TO THE SURFACE. STORMS IN THIS REGION COULD
PRODUCE HAIL LARGER THAN GOLF BALLS...DAMAGING STRAIGHT LINE
WINDS...AND ISOLATED TORNADOES.

THUNDERSTORMS WILL GRADUALLY EXIT THE REGION FROM WEST TO EAST
DURING THE EVENING.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT SATURDAY APR 14.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...70 PERCENT.

OTHER HAZARDOUS WEATHER...
HAZARDOUS WINTER WEATHER WILL AFFECT PARTS OF THE AREA. A SNOW
ADVISORY IS IN EFFECT FOR FAR NORTHWEST OKLAHOMA. PLEASE REFER TO
THE LATEST VERSION OF THIS PRODUCT FOR MORE INFORMATION.

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

THUNDERSTORM OUTLOOK...
THUNDERSTORMS ARE AGAIN IN THE FORECAST LATE MONDAY THROUGH TUESDAY.
MOISTURE AND INSTABILITY MAY BE LATE TO RETURN...BUT WITH ANOTHER
STRONG UPPER LEVEL SYSTEM...AN ISOLATED SEVERE STORM CANNOT BE RULED
OUT.

OTHER HAZARDOUS WEATHER...
NONE.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 7 AM
SATURDAY.

TY/11

In the hours before

Special weather statement, Apr 13, 4:08 PM CDT, 1 hour 7 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
408 PM CDT FRI APR 13 2007

OKZ044-132130-
COTTON OK-
408 PM CDT FRI APR 13 2007

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR COTTON COUNTY.

A SEVERE THUNDERSTORM WAS LOCATED 19 MILES SOUTH OF RANDLETT AT 408
PM CDT...MOVING NORTHEAST AT 40 MPH.  THIS STORM HAS A HISTORY OF
PRODUCING LARGE HAIL.  SOME WEAKENING OF THIS STORM IS LIKELY
BUT LARGE HAIL MAY OCCUR WITH THIS STORM ACROSS MAINLY EASTERN
COTTON COUNTY BY 430 PM.

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

Special weather statement, Apr 13, 4:13 PM CDT, 1 hour 2 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
413 PM CDT FRI APR 13 2007

OKZ018>020-026-132130-
LINCOLN OK-LOGAN OK-KINGFISHER OK-PAYNE OK-
413 PM CDT FRI APR 13 2007

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR KINGFISHER...LINCOLN...LOGAN
AND PAYNE COUNTIES.

ISOLATED STRONG THUNDERSTORMS WERE LOCATED NEAR DOVER...CRESCENT
AND PERKINS AT 413 PM CDT.  THE STORMS WERE MOVING NORTHEAST AT 35
MPH.  SMALL HAIL AND GUSTY WINDS ARE LIKELY WITH THESE STORMS.

SEVERE WEATHER IS NOT EXPECTED AND NO WARNINGS ARE ANTICIPATED AT
THIS TIME.

Local storm report, Apr 13, 4:14 PM CDT, 1 hour 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
414 PM CDT FRI APR 13 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0354 PM     HAIL             LAKESIDE CITY           33.83N 98.54W
04/13/2007  E1.25 INCH       ARCHER             TX   AMATEUR RADIO

&&

JLP

Local storm report, Apr 13, 4:26 PM CDT, 49 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
426 PM CDT FRI APR 13 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0415 PM     HAIL             DEAN                    33.93N 98.37W
04/13/2007  E1.25 INCH       CLAY               TX   PUBLIC

&&

JLP

Local storm report, Apr 13, 4:44 PM CDT, 31 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
444 PM CDT FRI APR 13 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0444 PM     HAIL             THORNBERRY              34.06N 98.39W
04/13/2007  E0.88 INCH       CLAY               TX   AMATEUR RADIO

&&

SMITH

Local storm report, Apr 13, 5:01 PM CDT, 14 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 13, 1:03 AM CDT	Severe Thunderstorm Warning	OUN	Greer	27 min
Apr 13, 1:30 AM CDT	Severe Thunderstorm Warning	OUN	Greer, Kiowa	45 min
Apr 13, 2:09 AM CDT	Severe Thunderstorm Warning	OUN	Washita	51 min
Apr 13, 2:56 AM CDT	Severe Thunderstorm Warning	OUN	Caddo	49 min
Apr 13, 3:40 AM CDT	Severe Thunderstorm Warning	OUN	Canadian	25 min
Apr 13, 3:45 AM CDT	Snow Advisory	OUN	Alfalfa, Ellis, Garfield, Grant, Harper, Kay and 4 more	27 hr
Apr 13, 3:48 AM CDT	Severe Thunderstorm Warning	OUN	Beckham	42 min
Apr 13, 3:55 AM CDT	Severe Thunderstorm Warning	OUN	Kingfisher	29 min
Apr 13, 4:13 AM CDT	Severe Thunderstorm Warning	OUN	Greer, Harmon	47 min
Apr 13, 5:07 AM CDT	Severe Thunderstorm Warning	OUN	Jackson, Kiowa	38 min
Apr 13, 5:42 AM CDT	Severe Thunderstorm Warning	OUN	Kiowa	48 min
Apr 13, 7:09 AM CDT	Severe Thunderstorm Warning	OUN	Marshall	36 min
Apr 13, 7:14 AM CDT	Severe Thunderstorm Warning	OUN	Harmon	46 min
Apr 13, 1:14 PM CDT	Severe Thunderstorm Warning	OUN	Seminole	46 min
Apr 13, 4:30 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson	45 min
Apr 13, 1:36 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Knox	39 min
Apr 13, 2:12 PM CDT	Tornado Warning	OUN	Baylor, Knox	33 min
Apr 13, 2:17 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Wilbarger	43 min
Apr 13, 2:40 PM CDT	Tornado Warning	OUN	Baylor	35 min
Apr 13, 3:05 PM CDT	Severe Thunderstorm Warning	OUN	Archer, Wichita	40 min
Apr 13, 3:16 PM CDT	Severe Thunderstorm Warning	OUN	Baylor	29 min
Apr 13, 3:16 PM CDT	Tornado Warning	OUN	Archer	44 min
Apr 13, 3:46 PM CDT	Severe Thunderstorm Warning	OUN	Clay, Wichita	44 min
Apr 13, 3:56 PM CDT	Tornado Warning	OUN	Archer	34 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2007 Every severe thunderstorm warning in 2007

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.