Alert archive / South Dakota / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 391

July 16, 201610 counties in Montana; 16 counties in South Dakota; 4 counties in Wyoming

The Storm Prediction Center issued this severe thunderstorm watch at Jul 16, 2016, 2:33 PM MDT for 10 counties in Montana; 16 counties in South Dakota; 4 counties in Wyoming. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jul 16, 2016, 2:33 PM MDT (20:33 UTC)
Expired: Jul 16, 2016, 9:00 PM MDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2.5 in
Strongest gust expected: 60 kt

All 30 counties

Big Horn County, MT, Carter County, MT, Custer County, MT, Fallon County, MT, Garfield County, MT, Powder River County, MT, Prairie County, MT, Rosebud County, MT, Treasure County, MT, Wibaux County, MT, Bennett County, SD, Butte County, SD, Custer County, SD, Fall River County, SD, Haakon County, SD, Harding County, SD, Jackson County, SD, Lawrence County, SD, Meade County, SD, Mellette County, SD, Oglala Lakota County, SD, Pennington County, SD, Perkins County, SD, Todd County, SD, Tripp County, SD, Ziebach County, SD, Campbell County, WY, Crook County, WY, Sheridan County, WY, Weston County, WY

The radar

The Billings radar (KBLX), 238 km from the middle of the area, began a volume at 20:35 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: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 50%
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: 30%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jul 16, 2:41 PM MDT	Severe Thunderstorm Warning	BYZ	Big Horn	64 min
Jul 16, 2:53 PM MDT	Severe Thunderstorm Warning	UNR	Meade, Pennington	52 min
Jul 16, 3:08 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	67 min
Jul 16, 3:10 PM MDT	Severe Thunderstorm Warning	UNR	Custer, Pennington	33 min
Jul 16, 3:15 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	60 min
Jul 16, 3:24 PM MDT	Severe Thunderstorm Warning	BYZ	Powder River	66 min
Jul 16, 3:31 PM MDT	Severe Thunderstorm Warning	BYZ	Big Horn	48 min
Jul 16, 3:43 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	32 min
Jul 16, 3:53 PM MDT	Severe Thunderstorm Warning	UNR	Campbell, Crook	52 min
Jul 16, 3:58 PM MDT	Severe Thunderstorm Warning	UNR	Custer	47 min
Jul 16, 4:17 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	43 min
Jul 16, 4:21 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Lawrence	39 min
Jul 16, 4:26 PM MDT	Severe Thunderstorm Warning	BYZ	Carter, Powder River	18 min
Jul 16, 4:34 PM MDT	Tornado Warning	UNR	Lawrence	19 min
Jul 16, 4:50 PM MDT	Severe Thunderstorm Warning	UNR	Butte	40 min
Jul 16, 4:58 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence, Meade	47 min
Jul 16, 5:21 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Lawrence, Meade	39 min
Jul 16, 5:28 PM MDT	Severe Thunderstorm Warning	UNR	Fall River, Oglala Lakota	47 min
Jul 16, 5:34 PM MDT	Severe Thunderstorm Warning	UNR	Lawrence, Meade, Pennington	41 min
Jul 16, 5:56 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Meade	49 min
Jul 16, 6:06 PM MDT	Severe Thunderstorm Warning	UNR	Bennett, Jackson, Oglala Lakota, Pennington	39 min
Jul 16, 6:25 PM MDT	Tornado Warning	UNR	Bennett, Oglala Lakota	23 min
Jul 16, 6:44 PM MDT	Severe Thunderstorm Warning	UNR	Jackson	33 min
Jul 16, 6:46 PM MDT	Severe Thunderstorm Warning	UNR	Bennett	19 min
Jul 16, 7:29 PM MDT	Severe Thunderstorm Warning	UNR	Meade, Perkins, Ziebach	41 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

Rapid City, SD (KRAP), launched 12:00Z, 8.6 hours before the alert went out and 284 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: 486 J/kg
Mixed-layer CIN: -347 J/kg
Mixed-layer LCL: 1277 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: -39 m²/s²
0-3 km storm-relative helicity: 52 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 16, 12:23 PM MDT	Mesoscale Discussion	SPC	Big Horn, Carbon, Custer, Golden Valley, Musselshell, Powder River and 5 more	3 hr
Jul 16, 11:27 AM MDT	Mesoscale Discussion	SPC	Brown, Campbell, Clark, Codington, Corson, Day and 15 more	2 hr
Jul 16, 12:09 PM MDT	Severe Thunderstorm Watch	SPC	Brown, Campbell, Clark, Codington, Corson, Day and 12 more	7 hr
Jul 16, 2:18 PM MDT	Mesoscale Discussion	SPC	Brown, Campbell, Clark, Codington, Corson, Day and 11 more	87 min
Jul 16, 4:09 PM MDT	Mesoscale Discussion	SPC	Aurora, Beadle, Brookings, Brown, Brule, Buffalo and 39 more	96 min
Jul 16, 5:57 PM MDT	Severe Thunderstorm Watch	SPC	Aurora, Beadle, Bon Homme, Brookings, Brown, Brule and 43 more	7 hr

Nearby

Severe Thunderstorm Watches in South Dakota, 2016 Severe Thunderstorm Watches in Montana, 2016 Severe Thunderstorm Watches in Wyoming, 2016 Every 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.