Alert archive / Montana / Mesoscale Discussions in 2020

Mesoscale Discussion 775

May 31, 20204 states

The Storm Prediction Center issued this mesoscale discussion at May 31, 2020, 2:35 PM MDT for 4 states. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: May 31, 2020, 2:35 PM MDT (20:35 UTC)
Expired: May 31, 2020, 4:30 PM MDT
In force: 115 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

Counties Big Horn County, MT, Carter County, MT, Custer County, MT, Dawson County, MT, Fallon County, MT, Powder River County, MT, Prairie County, MT, Rosebud County, MT, Treasure County, MT, Wibaux County, MT, Bowman County, ND, Golden Valley County, ND, Slope County, ND, Butte County, SD, Harding County, SD, Crook County, WY, Sheridan County, WY

The radar

The Billings radar (KBLX), 245 km from the middle of the area, began a volume at 20:36 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 238May 31, 4:05 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 12:00Z, 8.6 hours before the alert went out and 377 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2001 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 164 m²/s²
0-3 km storm-relative helicity: 291 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 30, 9:06 PM MDT	Mesoscale Discussion	SPC	Mineral, Sanders	114 min
May 31, 2:29 PM MDT	Mesoscale Discussion	SPC	Blaine, Daniels, Phillips, Valley	2 hr
May 31, 4:07 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Custer, Dawson, Fallon, Powder River, Prairie and 1 more	6 hr
May 31, 3:43 PM MDT	Mesoscale Discussion	SPC	Custer, Fall River, Oglala Lakota, Pennington	2 hr
May 31, 12:18 PM MDT	Mesoscale Discussion	SPC	Albany, Carbon, Fremont, Laramie, Natrona, Platte and 2 more	117 min

Nearby

Mesoscale Discussions in Montana, 2020 Mesoscale Discussions in North Dakota, 2020 Mesoscale Discussions in South Dakota, 2020 Every mesoscale discussion 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.