Alert archive / Minnesota / Mesoscale Discussions in 2017

Mesoscale Discussion 1664

September 22, 20179 counties in Minnesota; Douglas County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 22, 2017, 4:10 AM CDT for 9 counties in Minnesota; Douglas County, Wisconsin. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Sep 22, 2017, 4:10 AM CDT (09:10 UTC)
Expired: Sep 22, 2017, 6:45 AM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Aitkin County, MN, Carlton County, MN, Cass County, MN, Crow Wing County, MN, Morrison County, MN, Otter Tail County, MN, Pine County, MN, Todd County, MN, Wadena County, MN, Douglas County, WI

The radar

The Duluth radar (KDLH), 98 km from the middle of the area, began a volume at 09:09 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

Minneapolis, MN (KMPX), launched 00:00Z, 9.2 hours before the alert went out and 192 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: 1879 J/kg
Mixed-layer CIN: -70 J/kg
Mixed-layer LCL: 1223 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 278 m²/s²
0-3 km storm-relative helicity: 414 m²/s²
Significant tornado parameter: 1.6
Supercell composite: 15.2

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
Sep 21, 11:34 PM CDT	Mesoscale Discussion	SPC	Aitkin, Benton, Big Stone, Chisago, Crow Wing, Douglas and 12 more	116 min
Sep 22, 3:57 PM CDT	Mesoscale Discussion	SPC	Lac qui Parle, Lincoln, Lyon, Pipestone, Rock	2 hr
Sep 22, 10:20 AM CDT	Mesoscale Discussion	SPC	Florence, Forest, Iron, Langlade, Lincoln, Marinette and 6 more	85 min

Nearby

Mesoscale Discussions in Minnesota, 2017 Mesoscale Discussions in Wisconsin, 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.