Alert archive / Iowa / Mesoscale Discussions in 2015

Mesoscale Discussion 1769

September 6, 20155 states

The Storm Prediction Center issued this mesoscale discussion at Sep 6, 2015, 8:42 PM CDT for 5 states. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: Sep 6, 2015, 8:42 PM CDT (01:42 UTC)
Expired: Sep 6, 2015, 10:15 PM CDT
In force: 93 min
Issued by: the Storm Prediction Center

All 87 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Cerro Gordo County, IA, Chickasaw County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Floyd County, IA, Franklin County, IA, Fremont County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hancock County, IA, Hardin County, IA, Harrison County, IA, Howard County, IA, Humboldt County, IA, Jasper County, IA, Kossuth County, IA, Madison County, IA, Marshall County, IA, Mills County, IA, Mitchell County, IA, Montgomery County, IA, Page County, IA, Pocahontas County, IA, Polk County, IA, Pottawattamie County, IA, Ringgold County, IA, Sac County, IA, Shelby County, IA, Story County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Webster County, IA, Winnebago County, IA, Winneshiek County, IA, Worth County, IA, Wright County, IA, Dodge County, MN, Faribault County, MN, Fillmore County, MN, Freeborn County, MN, Goodhue County, MN, Houston County, MN, Mower County, MN, Olmsted County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Waseca County, MN, Winona County, MN, Atchison County, MO, Nodaway County, MO, Worth County, MO, Cass County, NE, Douglas County, NE, Gage County, NE, Johnson County, NE, Lancaster County, NE, Nemaha County, NE, Otoe County, NE, Richardson County, NE, Sarpy County, NE, Washington County, NE, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Jackson County, WI, La Crosse County, WI, Pepin County, WI, Pierce County, WI, Saint Croix County, WI, Trempealeau County, WI

The radar

The Des Moines radar (KDMX), 82 km from the middle of the area, began a volume at 01:42 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

Omaha, NE (KOAX), launched 00:00Z, 1.7 hours before the alert went out and 249 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: 1563 J/kg
Mixed-layer CIN: -79 J/kg
Mixed-layer LCL: 1693 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 121 m²/s²
0-3 km storm-relative helicity: 254 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 21.9

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 6, 11:41 PM CDT	Mesoscale Discussion	SPC	Adair, Adams, Allamakee, Audubon, Benton, Black Hawk and 38 more	64 min
Sep 7, 2:18 PM CDT	Mesoscale Discussion	SPC	Fremont, Mills, Page	87 min
Sep 6, 9:10 PM CDT	Mesoscale Discussion	SPC	Anoka, Chisago, Isanti, Kanabec, Pine, Sherburne and 1 more	65 min
Sep 7, 3:37 PM CDT	Severe Thunderstorm Watch	SPC	Franklin, Gage, Jefferson, Johnson, Nuckolls, Pawnee and 3 more	6 hr
Sep 7, 5:46 PM CDT	Mesoscale Discussion	SPC	Arthur, Blaine, Brown, Chase, Cherry, Cheyenne and 22 more	119 min
Sep 7, 6:23 PM CDT	Mesoscale Discussion	SPC	Gage, Jefferson, Nuckolls, Pawnee, Thayer, Webster	97 min
Sep 7, 6:50 PM CDT	Severe Thunderstorm Watch	SPC	Chase, Custer, Dawson, Dundy, Frontier, Furnas and 7 more	2 hr

Nearby

Mesoscale Discussions in Iowa, 2015 Mesoscale Discussions in Minnesota, 2015 Mesoscale Discussions in Wisconsin, 2015 Every mesoscale discussion in 2015

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.