Alert archive / Iowa / Mesoscale Discussions in 2020

Mesoscale Discussion 935

June 18, 20204 states

The Storm Prediction Center issued this mesoscale discussion at Jun 18, 2020, 6:30 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jun 18, 2020, 6:30 PM CDT (23:30 UTC)
Expired: Jun 18, 2020, 8:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 68 counties

Adair County, IA, Adams County, IA, Audubon County, IA, Cass County, IA, Clarke County, IA, Dallas County, IA, Decatur County, IA, Fremont County, IA, Guthrie County, IA, Harrison County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Marion County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Polk County, IA, Pottawattamie County, IA, Ringgold County, IA, Shelby County, IA, Taylor County, IA, Union County, IA, Warren County, IA, Wayne County, IA, Atchison County, KS, Brown County, KS, Clay County, KS, Cloud County, KS, Dickinson County, KS, Doniphan County, KS, Geary County, KS, Jackson County, KS, Jefferson County, KS, Leavenworth County, KS, Marshall County, KS, Morris County, KS, Nemaha County, KS, Ottawa County, KS, Pottawatomie County, KS, Riley County, KS, Saline County, KS, Shawnee County, KS, Wabaunsee County, KS, Washington County, KS, Andrew County, MO, Atchison County, MO, Buchanan County, MO, Clinton County, MO, Daviess County, MO, DeKalb County, MO, Gentry County, MO, Harrison County, MO, Holt County, MO, Mercer County, MO, Nodaway County, MO, Platte County, MO, Worth County, MO, Cass County, NE, Douglas County, NE, Gage County, NE, Jefferson County, NE, Johnson County, NE, Nemaha County, NE, Otoe County, NE, Pawnee County, NE, Richardson County, NE, Sarpy County, NE

The radar

The Omaha radar (KOAX), 135 km from the middle of the area, began a volume at 23:30 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

Topeka, KS (KTOP), launched 12:00Z, 11.5 hours before the alert went out and 134 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: 297 J/kg
Mixed-layer CIN: -249 J/kg
Mixed-layer LCL: 1205 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: -10 m²/s²
0-3 km storm-relative helicity: 92 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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
Jun 18, 3:39 PM CDT	Mesoscale Discussion	SPC	Buena Vista, Calhoun, Carroll, Cherokee, Clay, Crawford and 13 more	96 min
Jun 18, 3:48 PM CDT	Mesoscale Discussion	SPC	Adair, Audubon, Carroll, Cass, Crawford, Fremont and 8 more	117 min
Jun 17, 9:23 PM CDT	Mesoscale Discussion	SPC	Arthur, Brown, Cherry, Grant, Hooker, Keya Paha and 1 more	2 hr
Jun 17, 11:16 PM CDT	Mesoscale Discussion	SPC	Arthur, Blaine, Brown, Cherry, Grant, Hooker and 4 more	89 min

Nearby

Mesoscale Discussions in Iowa, 2020 Mesoscale Discussions in Kansas, 2020 Mesoscale Discussions in Missouri, 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.