Alert archive / Montana / Mesoscale Discussions in 2020

Mesoscale Discussion 1105

July 4, 202011 counties in Montana; 10 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2020, 8:46 PM MDT for 11 counties in Montana; 10 counties in North Dakota. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Jul 4, 2020, 8:46 PM MDT (02:46 UTC)
Expired: Jul 4, 2020, 10:45 PM MDT
In force: 119 min
Issued by: the Storm Prediction Center
Concerning: Severe thunderstorm watch 329

All 21 counties

Carter County, MT, Daniels County, MT, Dawson County, MT, Fallon County, MT, McCone County, MT, Prairie County, MT, Richland County, MT, Roosevelt County, MT, Sheridan County, MT, Valley County, MT, Wibaux County, MT, Billings County, ND, Bowman County, ND, Divide County, ND, Dunn County, ND, Golden Valley County, ND, Hettinger County, ND, McKenzie County, ND, Slope County, ND, Stark County, ND, Williams County, ND

The radar

The Glasgow radar (KGGW), 170 km from the middle of the area, began a volume at 02:47 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 330Jul 4, 9:45 PM MDT

The nearest sounding before it

Bismarck Municip, ND (KBIS), launched 00:00Z, 2.8 hours before the alert went out and 323 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: 902 J/kg
Mixed-layer CIN: -93 J/kg
Mixed-layer LCL: 1890 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 91 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

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
Jul 4, 6:50 PM MDT	Mesoscale Discussion	SPC	Custer, Garfield, McCone, Phillips, Powder River, Prairie and 1 more	55 min
Jul 5, 3:00 PM MDT	Mesoscale Discussion	SPC	Big Horn	2 hr
Jul 5, 4:13 PM MDT	Severe Thunderstorm Watch	SPC	Carter, Powder River	7 hr
Jul 4, 9:42 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Billings, Bowman, Burke, Divide, Dunn and 9 more	5 hr
Jul 5, 12:25 AM MDT	Mesoscale Discussion	SPC	Adams, Burke, Divide, Dunn, Grant, Hettinger and 11 more	2 hr
Jul 5, 2:32 PM MDT	Mesoscale Discussion	SPC	Dickey, LaMoure, McIntosh, Ransom, Sargent	118 min
Jul 5, 3:41 PM MDT	Severe Thunderstorm Watch	SPC	Adams, Barnes, Bowman, Burleigh, Cass, Dickey and 13 more	6 hr
Jul 5, 5:29 PM MDT	Mesoscale Discussion	SPC	Adams, Dickey, Emmons, Grant, Hettinger, LaMoure and 6 more	2 hr

Nearby

Mesoscale Discussions in Montana, 2020 Mesoscale Discussions in North 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.