Alert archive / Oklahoma / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 83

April 11, 2016Crawford County, Sebastian County, Washington County, Arkansas; 16 counties in Oklahoma

The Storm Prediction Center issued this severe thunderstorm watch at Apr 11, 2016, 12:57 AM CDT for Crawford County, Sebastian County, Washington County, Arkansas; 16 counties in Oklahoma. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 11, 2016, 12:57 AM CDT (05:57 UTC)
Expired
Apr 11, 2016, 4:45 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt

Counties Crawford County, AR, Sebastian County, AR, Washington County, AR, Adair County, OK, Cherokee County, OK, Choctaw County, OK, Creek County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK

The radar

The Tulsa radar (KINX), 109 km from the middle of the area, began a volume at 05:56 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
20%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 11, 1:34 AM CDTSevere Thunderstorm WarningTSACreek26 min
Apr 11, 1:47 AM CDTSevere Thunderstorm WarningTSACreek, Pawnee28 min
Apr 11, 2:02 AM CDTSevere Thunderstorm WarningTSACreek, Osage, Tulsa43 min

Discussions around it

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

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 6.0 hours before the alert went out and 158 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, Norman, OK at 00:00Z on 2016-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2443 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, Norman, OK at 00:00Z on 2016-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 166 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
2443 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
1418 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
166 m²/s²
0-3 km storm-relative helicity
243 m²/s²
Significant tornado parameter
1.2
Supercell composite
13.4

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 11:48 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 15 more2 hr
Apr 11, 1:05 PM CDTSevere Thunderstorm WatchSPCAshley, Bradley, Calhoun, Chicot, Columbia, Desha and 5 more6 hr
Apr 11, 1:38 PM CDTSevere Thunderstorm WatchSPCHempstead, Howard, Little River, Miller, Polk, Sevier9 hr
Apr 11, 3:42 PM CDTMesoscale DiscussionSPCAshley, Bradley, Chicot, Columbia, Drew, Union93 min
Apr 11, 6:09 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Columbia, Drew and 2 more66 min
Apr 10, 7:36 PM CDTMesoscale DiscussionSPCBlaine, Caddo, Canadian, Carter, Cleveland, Coal and 23 more114 min
Apr 10, 8:42 PM CDTMesoscale DiscussionSPCCraig, Kay, Nowata, Osage, Ottawa, Rogers and 1 more2 hr
Apr 10, 9:31 PM CDTMesoscale DiscussionSPCBeckham, Caddo, Canadian, Carter, Cleveland, Comanche and 17 more59 min
Apr 10, 9:52 PM CDTSevere Thunderstorm WatchSPCAtoka, Bryan, Caddo, Canadian, Carter, Cleveland and 24 more6 hr
Apr 10, 11:23 PM CDTMesoscale DiscussionSPCCraig, Nowata, Osage, Ottawa, Rogers, Washington37 min
Apr 11, 12:21 AM CDTMesoscale DiscussionSPCCarter, Cleveland, Coal, Garvin, Hughes, Jefferson and 10 more54 min
Apr 11, 6:15 AM CDTMesoscale DiscussionSPCBryan, Carter, Choctaw, Jefferson, Johnston, Love and 1 more3 hr
Apr 11, 12:39 PM CDTMesoscale DiscussionSPCCarter, Jefferson, Love, Marshall2 hr

Nearby

Severe Thunderstorm Watches in Oklahoma, 2016Severe Thunderstorm Watches in Arkansas, 2016Every severe thunderstorm watch in 2016

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.