Alert archive / Wyoming / Severe Thunderstorm Watches in 2020

Severe Thunderstorm Watch 263

June 6, 20208 counties in Nebraska; 13 counties in Wyoming

The Storm Prediction Center issued this severe thunderstorm watch at Jun 6, 2020, 1:23 PM MDT for 8 counties in Nebraska; 13 counties in Wyoming. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jun 6, 2020, 1:23 PM MDT (19:23 UTC)
Expired: Jun 6, 2020, 8:00 PM MDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 65 kt

All 21 counties

Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Albany County, WY, Campbell County, WY, Carbon County, WY, Converse County, WY, Crook County, WY, Goshen County, WY, Johnson County, WY, Laramie County, WY, Natrona County, WY, Niobrara County, WY, Platte County, WY, Sweetwater County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 207 km from the middle of the area, began a volume at 19:25 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: 60%
One or more gusts of 65 knots or more: 60%
Ten or more severe hail reports: 40%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 90%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 6, 1:26 PM MDT	Severe Thunderstorm Warning	RIW	Sweetwater	64 min
Jun 6, 1:28 PM MDT	Severe Thunderstorm Warning	CYS	Carbon	62 min
Jun 6, 2:09 PM MDT	Severe Thunderstorm Warning	CYS	Carbon	66 min
Jun 6, 2:10 PM MDT	Severe Thunderstorm Warning	RIW	Sweetwater	50 min
Jun 6, 2:29 PM MDT	Severe Thunderstorm Warning	CYS	Carbon	31 min
Jun 6, 2:32 PM MDT	Severe Thunderstorm Warning	RIW	Fremont, Natrona	58 min
Jun 6, 2:53 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Carbon	67 min
Jun 6, 3:02 PM MDT	Tornado Warning	CYS	Albany, Carbon	28 min
Jun 6, 3:34 PM MDT	Severe Thunderstorm Warning	RIW	Fremont, Natrona	56 min
Jun 6, 3:40 PM MDT	Severe Thunderstorm Warning	CYS	Albany, Converse, Platte	65 min
Jun 6, 3:53 PM MDT	Severe Thunderstorm Warning	RIW	Johnson, Natrona	37 min
Jun 6, 4:08 PM MDT	Severe Thunderstorm Warning	CYS	Laramie	52 min
Jun 6, 4:23 PM MDT	Severe Thunderstorm Warning	CYS	Goshen, Laramie	37 min
Jun 6, 4:29 PM MDT	Severe Thunderstorm Warning	UNR	Campbell, Crook, Weston	61 min
Jun 6, 4:35 PM MDT	Severe Thunderstorm Warning	RIW	Johnson	25 min
Jun 6, 4:39 PM MDT	Severe Thunderstorm Warning	CYS	Converse, Goshen, Niobrara, Platte	51 min
Jun 6, 4:56 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Kimball, Scotts Bluff	49 min
Jun 6, 5:02 PM MDT	Severe Thunderstorm Warning	RIW	Big Horn, Johnson	30 min
Jun 6, 5:09 PM MDT	Severe Thunderstorm Warning	UNR	Campbell, Crook, Weston	66 min
Jun 6, 5:14 PM MDT	Severe Thunderstorm Warning	CYS	Sioux	31 min
Jun 6, 5:28 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Cheyenne, Kimball, Morrill	77 min
Jun 6, 5:32 PM MDT	Severe Thunderstorm Warning	CYS	Banner, Box Butte, Dawes, Morrill, Scotts Bluff, Sioux	43 min
Jun 6, 5:42 PM MDT	Severe Thunderstorm Warning	CYS	Sioux	33 min
Jun 6, 5:58 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Dawes, Morrill, Scotts Bluff, Sioux	77 min
Jun 6, 6:09 PM MDT	Severe Thunderstorm Warning	UNR	Crook, Weston	36 min
Jun 6, 6:40 PM MDT	Severe Thunderstorm Warning	UNR	Crook	65 min
Jun 6, 7:30 PM MDT	Severe Thunderstorm Warning	CYS	Box Butte, Cheyenne, Dawes, Morrill	29 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 (KUNR), launched 12:00Z, 7.4 hours before the alert went out and 201 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: 39 J/kg
Mixed-layer CIN: -739 J/kg
Mixed-layer LCL: 1598 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -52 m²/s²
0-3 km storm-relative helicity: -15 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 5, 7:01 PM MDT	Mesoscale Discussion	SPC	Banner, Box Butte, Cheyenne, Dawes, Morrill, Scotts Bluff and 2 more	119 min
Jun 6, 2:33 PM MDT	Mesoscale Discussion	SPC	Arthur, Box Butte, Cherry, Cheyenne, Dawes, Deuel and 12 more	117 min
Jun 6, 4:49 PM MDT	Severe Thunderstorm Watch	SPC	Arthur, Blaine, Brown, Chase, Cherry, Deuel and 12 more	6 hr
Jun 6, 5:25 PM MDT	Mesoscale Discussion	SPC	Box Butte, Dawes, Morrill, Scotts Bluff, Sheridan, Sioux	95 min
Jun 5, 6:24 PM MDT	Mesoscale Discussion	SPC	Uinta	96 min
Jun 6, 9:48 AM MDT	Severe Thunderstorm Watch	SPC	Uinta	6 hr
Jun 6, 12:27 PM MDT	Mesoscale Discussion	SPC	Albany, Campbell, Carbon, Converse, Crook, Goshen and 7 more	93 min

Nearby

Severe Thunderstorm Watches in Wyoming, 2020 Severe Thunderstorm Watches in Nebraska, 2020 Every severe thunderstorm watch in 2020

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.