Alert archive / Montana / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 143

June 1, 20184 states

The Storm Prediction Center issued this severe thunderstorm watch at Jun 1, 2018, 11:45 AM MDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Jun 1, 2018, 11:45 AM MDT (17:45 UTC)
Expired: Jun 1, 2018, 5:47 PM MDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2.5 in
Strongest gust expected: 60 kt

All 29 counties

Big Horn County, MT, Carter County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Powder River County, MT, Prairie County, MT, Richland County, MT, Rosebud County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Golden Valley County, ND, Hettinger County, ND, Slope County, ND, Stark County, ND, Butte County, SD, Harding County, SD, Lawrence County, SD, Meade County, SD, Perkins County, SD, Campbell County, WY, Crook County, WY, Johnson County, WY, Sheridan County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 240 km from the middle of the area, began a volume at 17:46 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: 5%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 70%
One or more hailstones of 2 inches or more: 60%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 1, 12:03 PM MDT	Tornado Warning	RIW	Johnson, Washakie	27 min
Jun 1, 12:08 PM MDT	Severe Thunderstorm Warning	BYZ	Rosebud	67 min
Jun 1, 12:53 PM MDT	Severe Thunderstorm Warning	BYZ	Powder River	67 min
Jun 1, 12:58 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	17 min
Jun 1, 1:01 PM MDT	Severe Thunderstorm Warning	BYZ	Custer, Rosebud	44 min
Jun 1, 1:36 PM MDT	Severe Thunderstorm Warning	UNR	Campbell	39 min
Jun 1, 1:37 PM MDT	Severe Thunderstorm Warning	GGW	McCone, Prairie	53 min
Jun 1, 1:40 PM MDT	Tornado Warning	UNR	Campbell	35 min
Jun 1, 1:59 PM MDT	Severe Thunderstorm Warning	UNR	Campbell, Crook	46 min
Jun 1, 2:05 PM MDT	Tornado Warning Tornado observed	UNR	Campbell	25 min
Jun 1, 2:10 PM MDT	Tornado Warning	UNR	Crook	35 min
Jun 1, 2:15 PM MDT	Severe Thunderstorm Warning	GGW	Dawson, McCone, Prairie	60 min
Jun 1, 2:29 PM MDT	Tornado Warning Considerable damage threat	UNR	Crook	46 min
Jun 1, 3:04 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Harding	56 min
Jun 1, 3:07 PM MDT	Severe Thunderstorm Warning	BIS	Billings, McKenzie	53 min
Jun 1, 3:27 PM MDT	Severe Thunderstorm Warning	GGW	Richland	48 min
Jun 1, 3:32 PM MDT	Severe Thunderstorm Warning	UNR	Butte	28 min
Jun 1, 3:32 PM MDT	Tornado Warning	UNR	Butte, Harding	28 min
Jun 1, 3:41 PM MDT	Tornado Warning	UNR	Butte	19 min
Jun 1, 3:58 PM MDT	Severe Thunderstorm Warning	UNR	Butte, Meade, Perkins	47 min
Jun 1, 4:03 PM MDT	Severe Thunderstorm Warning	GGW	Richland, Roosevelt, Sheridan	57 min
Jun 1, 4:34 PM MDT	Severe Thunderstorm Warning	UNR	Meade	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, 5.8 hours before the alert went out and 243 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: 1239 J/kg
Mixed-layer CIN: -286 J/kg
Mixed-layer LCL: 1849 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 65 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
May 31, 8:18 PM MDT	Mesoscale Discussion	SPC	Big Horn, Carter, Custer, Fallon, Musselshell, Powder River and 4 more	57 min
Jun 1, 11:03 AM MDT	Mesoscale Discussion	SPC	Big Horn, Carter, Custer, Dawson, Fallon, McCone and 4 more	117 min
Jun 1, 3:04 PM MDT	Mesoscale Discussion	SPC	Carter, Custer, Dawson, Fallon, Powder River, Prairie and 1 more	86 min
May 31, 6:00 PM MDT	Mesoscale Discussion	SPC	Adams, Burleigh, Emmons, Grant, Hettinger, Kidder and 3 more	90 min
Jun 1, 1:13 PM MDT	Mesoscale Discussion	SPC	Adams, Billings, Burke, Burleigh, Dunn, Emmons and 19 more	2 hr
Jun 1, 2:30 PM MDT	Tornado Watch	SPC	Bottineau, Burke, Burleigh, Divide, Dunn, Emmons and 18 more	6 hr
Jun 1, 5:02 PM MDT	Mesoscale Discussion	SPC	Bottineau, Burke, Burleigh, Divide, Dunn, Emmons and 15 more	88 min
Jun 1, 1:53 PM MDT	Severe Thunderstorm Watch	SPC	Aurora, Bon Homme, Brule, Buffalo, Campbell, Charles Mix and 22 more	7 hr
Jun 1, 5:32 PM MDT	Mesoscale Discussion	SPC	Aurora, Beadle, Bon Homme, Brule, Buffalo, Campbell and 22 more	88 min

Nearby

Severe Thunderstorm Watches in Montana, 2018 Severe Thunderstorm Watches in North Dakota, 2018 Severe Thunderstorm Watches in South Dakota, 2018 Every severe thunderstorm watch in 2018

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.