Alert archive / Illinois / Mesoscale Discussions in 2020

Mesoscale Discussion 300

April 7, 202024 counties in Illinois; Lake County, Porter County, Indiana; 6 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2020, 7:22 PM CDT for 24 counties in Illinois; Lake County, Porter County, Indiana; 6 counties in Iowa. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 7, 2020, 7:22 PM CDT (00:22 UTC)
Expired: Apr 7, 2020, 8:45 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center

All 32 counties

Cedar County, IA, Clinton County, IA, Jackson County, IA, Johnson County, IA, Muscatine County, IA, Scott County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Henry County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Marshall County, IL, McHenry County, IL, Mercer County, IL, Ogle County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Lake County, IN, Porter County, IN

The radar

The Quad Cities radar (KDVN), 80 km from the middle of the area, began a volume at 00:23 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 00:00Z, 0.4 hours before the alert went out and 73 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: 1200 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 1453 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 70 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.8

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
Apr 7, 11:20 PM CDT	Mesoscale Discussion	SPC	Champaign, Christian, Coles, Douglas, Edgar, Macon and 3 more	85 min
Apr 8, 1:46 PM CDT	Mesoscale Discussion	SPC	Adams, Bond, Brown, Calhoun, Cass, Champaign and 43 more	119 min
Apr 8, 3:08 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Bond, Brown, Bureau, Calhoun, Cass and 58 more	6 hr
Apr 8, 3:45 PM CDT	Mesoscale Discussion	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 14 more	2 hr
Apr 8, 4:24 PM CDT	Tornado Watch	SPC	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 14 more	7 hr
Apr 7, 8:07 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Allen, Blackford, Cass, DeKalb, Elkhart and 18 more	6 hr
Apr 7, 9:04 PM CDT	Mesoscale Discussion	SPC	Adams, Allen, DeKalb, Fulton, Huntington, Kosciusko and 6 more	86 min
Apr 8, 5:52 PM CDT	Mesoscale Discussion	SPC	Bartholomew, Boone, Brown, Clark, Clay, Clinton and 52 more	2 hr
Apr 8, 6:24 PM CDT	Tornado Watch	SPC	Bartholomew, Boone, Brown, Carroll, Clark, Clay and 51 more	5 hr

Nearby

Mesoscale Discussions in Illinois, 2020 Mesoscale Discussions in Iowa, 2020 Mesoscale Discussions in Indiana, 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.