Alert archive / Montana / Mesoscale Discussions in 2018

Mesoscale Discussion 535

May 26, 201810 counties in Montana; 9 counties in North Dakota; Harding County, Perkins County, South Dakota

The Storm Prediction Center issued this mesoscale discussion at May 26, 2018, 9:13 PM MDT for 10 counties in Montana; 9 counties in North Dakota; Harding County, Perkins County, South Dakota. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 26, 2018, 9:13 PM MDT (03:13 UTC)
Expired: May 26, 2018, 11:15 PM MDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 21 counties

Custer County, MT, Dawson County, MT, Fallon County, MT, Garfield County, MT, McCone County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Valley County, MT, Wibaux County, MT, Adams County, ND, Billings County, ND, Bowman County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Slope County, ND, Stark County, ND, Harding County, SD, Perkins County, SD

The radar

The Glasgow radar (KGGW), 193 km from the middle of the area, began a volume at 03:16 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 nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 00:00Z, 3.2 hours before the alert went out and 193 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: 1409 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 2385 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.0

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 27, 12:29 AM MDT	Mesoscale Discussion	SPC	Fallon, Wibaux	3 hr
May 27, 4:42 PM MDT	Mesoscale Discussion	SPC	Fall River	93 min
May 27, 5:06 PM MDT	Mesoscale Discussion	SPC	Bennett, Buffalo, Butte, Corson, Custer, Dewey and 22 more	84 min
May 27, 5:27 PM MDT	Severe Thunderstorm Watch	SPC	Bennett, Butte, Custer, Dewey, Fall River, Haakon and 16 more	6 hr

Nearby

Mesoscale Discussions in Montana, 2018 Mesoscale Discussions in North Dakota, 2018 Mesoscale Discussions in South Dakota, 2018 Every mesoscale discussion 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.