Alert archive / Iowa / Mesoscale Discussions in 2018

Mesoscale Discussion 1555

October 9, 201827 counties in Iowa; 19 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Oct 9, 2018, 6:37 PM CDT for 27 counties in Iowa; 19 counties in Wisconsin. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Oct 9, 2018, 6:37 PM CDT (23:37 UTC)
Expired: Oct 9, 2018, 8:00 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center

All 46 counties

Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Bremer County, IA, Buchanan County, IA, Clayton County, IA, Davis County, IA, Delaware County, IA, Dubuque County, IA, Fayette County, IA, Grundy County, IA, Iowa County, IA, Jasper County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Linn County, IA, Lucas County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Poweshiek County, IA, Tama County, IA, Wapello County, IA, Wayne County, IA, Adams County, WI, Calumet County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Fond du Lac County, WI, Grant County, WI, Green Lake County, WI, Iowa County, WI, Juneau County, WI, Lafayette County, WI, Marquette County, WI, Monroe County, WI, Outagamie County, WI, Richland County, WI, Sauk County, WI, Vernon County, WI, Waushara County, WI, Winnebago County, WI

The radar

The Quad Cities radar (KDVN), 120 km from the middle of the area, began a volume at 23:36 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

Davenport, (KDVN), launched 12:00Z, 11.6 hours before the alert went out and 121 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: 459 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 1071 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.7

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
Oct 8, 7:03 PM CDT	Mesoscale Discussion	SPC	Appanoose, Clarke, Dallas, Decatur, Jasper, Lucas and 9 more	57 min
Oct 9, 12:59 PM CDT	Mesoscale Discussion	SPC	Appanoose, Benton, Buchanan, Clarke, Davis, Decatur and 19 more	3 hr
Oct 9, 1:46 PM CDT	Tornado Watch	SPC	Adair, Adams, Appanoose, Benton, Black Hawk, Boone and 36 more	7 hr
Oct 9, 2:45 PM CDT	Mesoscale Discussion	SPC	Cedar, Clinton, Dubuque, Jackson, Jones, Muscatine and 1 more	2 hr
Oct 9, 3:53 PM CDT	Mesoscale Discussion	SPC	Appanoose, Benton, Black Hawk, Boone, Buchanan, Clarke and 29 more	2 hr
Oct 9, 5:09 PM CDT	Tornado Watch	SPC	Allamakee, Clayton, Fayette	4 hr

Nearby

Mesoscale Discussions in Iowa, 2018 Mesoscale Discussions in Wisconsin, 2018 Every mesoscale discussion in 2018

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.