Alert archive / Wisconsin / Mesoscale Discussions in 2020

Mesoscale Discussion 1306

July 21, 2020Houston County, Wabasha County, Winona County, Minnesota; 24 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2020, 6:13 PM CDT for Houston County, Wabasha County, Winona County, Minnesota; 24 counties in Wisconsin. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: Jul 21, 2020, 6:13 PM CDT (23:13 UTC)
Expired: Jul 21, 2020, 7:15 PM CDT
In force: 62 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 27 counties

Houston County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Barron County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, Juneau County, WI, La Crosse County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Richland County, WI, Rusk County, WI, Saint Croix County, WI, Sauk County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Vernon County, WI, Washburn County, WI, Wood County, WI

The radar

The La Crosse radar (KARX), 111 km from the middle of the area, began a volume at 23:13 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 12:00Z, 11.2 hours before the alert went out and 186 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: 148 J/kg
Mixed-layer CIN: -84 J/kg
Mixed-layer LCL: 1094 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 159 m²/s²
0-3 km storm-relative helicity: 214 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.7

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, 1:43 PM CDT	Mesoscale Discussion	SPC	Anoka, Blue Earth, Carver, Chisago, Dakota, Dodge and 23 more	2 hr

Nearby

Mesoscale Discussions in Wisconsin, 2020 Mesoscale Discussions in Minnesota, 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.