Alert archive / Minnesota / Mesoscale Discussions in 2014

Mesoscale Discussion 1745

September 20, 20144 counties in Iowa; 20 counties in Minnesota; 9 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 20, 2014, 5:23 PM CDT for 4 counties in Iowa; 20 counties in Minnesota; 9 counties in Wisconsin. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Sep 20, 2014, 5:23 PM CDT (22:23 UTC)
Expired: Sep 20, 2014, 6:30 PM CDT
In force: 67 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 33 counties

Allamakee County, IA, Howard County, IA, Mitchell County, IA, Winneshiek County, IA, Blue Earth County, MN, Carver County, MN, Dakota County, MN, Dodge County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Houston County, MN, Le Sueur County, MN, Mower County, MN, Nicollet County, MN, Olmsted County, MN, Rice County, MN, Scott County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Watonwan County, MN, Winona County, MN, Buffalo County, WI, Crawford County, WI, Jackson County, WI, La Crosse County, WI, Monroe County, WI, Pepin County, WI, Pierce County, WI, Trempealeau County, WI, Vernon County, WI

The radar

The La Crosse radar (KARX), 124 km from the middle of the area, began a volume at 22:24 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 506Sep 20, 5:45 PM CDT

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 10.4 hours before the alert went out and 125 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: 295 J/kg
Mixed-layer CIN: -178 J/kg
Mixed-layer LCL: 1113 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: -28 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 19, 10:34 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Cherokee, Clay, Dickinson, Emmet, Kossuth and 6 more	116 min
Sep 19, 11:45 PM CDT	Mesoscale Discussion	SPC	Butler, Calhoun, Cerro Gordo, Floyd, Franklin, Hamilton and 8 more	2 hr
Sep 20, 5:42 PM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Cerro Gordo, Chickasaw, Emmet, Floyd, Hancock and 7 more	3 hr
Sep 20, 6:56 PM CDT	Mesoscale Discussion	SPC	Davis, Des Moines, Henry, Jefferson, Lee, Louisa and 4 more	2 hr
Sep 20, 12:16 PM CDT	Mesoscale Discussion	SPC	Aitkin, Becker, Beltrami, Benton, Big Stone, Brown and 38 more	59 min
Sep 20, 1:26 PM CDT	Severe Thunderstorm Watch	SPC	Aitkin, Anoka, Becker, Beltrami, Benton, Big Stone and 58 more	6 hr
Sep 20, 3:57 PM CDT	Mesoscale Discussion	SPC	Aitkin, Anoka, Benton, Brown, Carver, Cass and 30 more	93 min
Sep 20, 5:55 PM CDT	Mesoscale Discussion	SPC	Clay, Norman, Polk	95 min

Nearby

Mesoscale Discussions in Minnesota, 2014 Mesoscale Discussions in Wisconsin, 2014 Mesoscale Discussions in Iowa, 2014 Every mesoscale discussion in 2014

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.