Alert archive / Minnesota / Mesoscale Discussions in 2017

Mesoscale Discussion 1379

July 21, 20178 counties in Minnesota; 4 counties in North Dakota

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2017, 12:47 PM CDT for 8 counties in Minnesota; 4 counties in North Dakota. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jul 21, 2017, 12:47 PM CDT (17:47 UTC)
Expired: Jul 21, 2017, 2:15 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Clearwater County, MN, Kittson County, MN, Mahnomen County, MN, Marshall County, MN, Norman County, MN, Pennington County, MN, Polk County, MN, Red Lake County, MN, Grand Forks County, ND, Pembina County, ND, Traill County, ND, Walsh County, ND

The radar

The Fargo/Grand Forks radar (KMVX), 70 km from the middle of the area, began a volume at 17:49 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 428Jul 21, 3:05 PM CDT

The nearest sounding before it

International Fa, MN (KINL), launched 12:00Z, 5.8 hours before the alert went out and 253 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: 1908 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 84 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
Jul 21, 9:42 AM CDT	Mesoscale Discussion	SPC	Kittson, Marshall	93 min
Jul 21, 2:20 PM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Clay, Clearwater, Hubbard, Mahnomen and 7 more	2 hr
Jul 21, 3:07 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Becker, Beltrami, Carlton, Cass, Clay and 14 more	10 hr
Jul 21, 3:53 PM CDT	Mesoscale Discussion	SPC	Becker, Beltrami, Clay, Clearwater, Mahnomen, Norman and 4 more	97 min
Jul 21, 6:25 PM CDT	Mesoscale Discussion	SPC	Aitkin, Becker, Benton, Big Stone, Carlton, Cass and 16 more	95 min
Jul 20, 7:31 PM CDT	Mesoscale Discussion	SPC	Emmons, Grant, Morton, Sioux	89 min

Nearby

Mesoscale Discussions in Minnesota, 2017 Mesoscale Discussions in North Dakota, 2017 Every mesoscale discussion in 2017

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.