Alert archive / Oklahoma / Tornado Watches in 2013

Tornado Watch 120

April 17, 20135 counties in Arkansas; 34 counties in Oklahoma

The Storm Prediction Center issued this tornado watch at Apr 17, 2013, 10:47 PM CDT for 5 counties in Arkansas; 34 counties in Oklahoma. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Apr 17, 2013, 10:47 PM CDT (03:47 UTC)
Expired: Apr 18, 2013, 6:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 39 counties

Benton County, AR, Carroll County, AR, Crawford County, AR, Madison County, AR, Washington County, AR, Adair County, OK, Atoka County, OK, Bryan County, OK, Carter County, OK, Cherokee County, OK, Coal County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Garvin County, OK, Haskell County, OK, Hughes County, OK, Jefferson County, OK, Johnston County, OK, Latimer County, OK, Love County, OK, Marshall County, OK, Mayes County, OK, McIntosh County, OK, Murray County, OK, Muskogee County, OK, Nowata County, OK, Okfuskee County, OK, Okmulgee County, OK, Ottawa County, OK, Pittsburg County, OK, Pontotoc County, OK, Pottawatomie County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Stephens County, OK, Tulsa County, OK, Wagoner County, OK

The radar

The Tulsa radar (KINX), 80 km from the middle of the area, began a volume at 03:48 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

18 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Apr 17, 11:00 PM CDT	Severe Thunderstorm Warning	TSA	Creek, Okfuskee, Okmulgee, Tulsa	60 min
Apr 17, 11:12 PM CDT	Tornado Warning	TSA	Creek, Okmulgee	33 min
Apr 17, 11:23 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Hughes, McClain, Pottawatomie, Seminole	82 min
Apr 17, 11:30 PM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Hughes, McClain, Pottawatomie, Seminole	75 min
Apr 17, 11:44 PM CDT	Tornado Warning	TSA	Creek, Okmulgee, Rogers, Tulsa, Wagoner	31 min
Apr 17, 11:53 PM CDT	Severe Thunderstorm Warning	TSA	Mayes, Muskogee, Okmulgee, Rogers, Tulsa, Wagoner	52 min
Apr 18, 12:17 AM CDT	Flash Flood Warning	TSA	Creek, Muskogee, Okfuskee, Okmulgee, Rogers, Tulsa and 1 more	4 hr
Apr 18, 12:17 AM CDT	Tornado Warning	TSA	Mayes, Rogers, Tulsa, Wagoner	28 min
Apr 18, 12:38 AM CDT	Severe Thunderstorm Warning	TSA	Adair, Cherokee, Delaware, Mayes, Muskogee, Okmulgee and 2 more	67 min
Apr 18, 12:46 AM CDT	Tornado Warning	TSA	Delaware, Mayes	29 min
Apr 18, 1:00 AM CDT	Flash Flood Warning	TSA	Cherokee, Craig, Delaware, Mayes, Muskogee, Ottawa and 2 more	4 hr
Apr 18, 1:16 AM CDT	Tornado Warning	TSA	Delaware, Mayes, Ottawa	44 min
Apr 18, 1:53 AM CDT	Tornado Warning	TSA	Adair, Cherokee, Delaware	37 min
Apr 18, 2:19 AM CDT	Severe Thunderstorm Warning	TSA	Benton, Washington	56 min
Apr 18, 2:39 AM CDT	Tornado Warning	TSA	Benton, Washington	51 min
Apr 18, 3:11 AM CDT	Severe Thunderstorm Warning	TSA	Cherokee, McIntosh, Muskogee, Okmulgee, Wagoner	64 min
Apr 18, 3:16 AM CDT	Flash Flood Warning	TSA	Benton, Washington	4 hr
Apr 18, 3:24 AM CDT	Flash Flood Warning	OUN	Lincoln, Pottawatomie, Seminole	4 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Lamont, OK (KLMN), launched 00:00Z, 3.8 hours before the alert went out and 198 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: 1 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 457 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 327 m²/s²
0-3 km storm-relative helicity: 520 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 18, 2:01 AM CDT	Mesoscale Discussion	SPC	Benton, Boone, Carroll, Crawford, Franklin, Madison and 2 more	89 min
Apr 18, 4:02 AM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Carroll, Conway, Crawford, Franklin and 17 more	58 min
Apr 18, 7:26 AM CDT	Mesoscale Discussion	SPC	Baxter, Boone, Clay, Cleburne, Conway, Craighead and 20 more	2 hr
Apr 18, 9:25 AM CDT	Tornado Watch	SPC	Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 43 more	8 hr
Apr 18, 12:48 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Clay and 29 more	87 min
Apr 18, 1:43 PM CDT	Tornado Watch	SPC	Ashley, Chicot, Union	8 hr
Apr 17, 8:36 PM CDT	Mesoscale Discussion	SPC	Caddo, Canadian, Carter, Cherokee, Cleveland, Coal and 41 more	84 min
Apr 17, 10:37 PM CDT	Mesoscale Discussion	SPC	Caddo, Canadian, Carter, Cherokee, Cleveland, Comanche and 35 more	53 min
Apr 17, 11:46 PM CDT	Mesoscale Discussion	SPC	Craig, Ottawa	89 min
Apr 18, 4:29 AM CDT	Mesoscale Discussion	SPC	Marshall	91 min

Nearby

Tornado Watches in Oklahoma, 2013 Tornado Watches in Arkansas, 2013 Every tornado watch in 2013

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.