Alert archive / Illinois / Mesoscale Discussions in 2020

Mesoscale Discussion 842

June 5, 20205 states

The Storm Prediction Center issued this mesoscale discussion at Jun 5, 2020, 12:26 PM CDT for 5 states. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Jun 5, 2020, 12:26 PM CDT (17:26 UTC)
Expired: Jun 5, 2020, 2:00 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

All 41 counties

Clinton County, IA, Jackson County, IA, Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Elkhart County, IN, Lake County, IN, LaPorte County, IN, Porter County, IN, Saint Joseph County, IN, Allegan County, MI, Berrien County, MI, Cass County, MI, Kalamazoo County, MI, Saint Joseph County, MI, Van Buren County, MI, Green County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Chicago radar (KLOT), 40 km from the middle of the area, began a volume at 17:27 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, 5.4 hours before the alert went out and 206 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: 897 J/kg
Mixed-layer CIN: -120 J/kg
Mixed-layer LCL: 1088 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.3

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 4, 10:50 PM CDT	Mesoscale Discussion	SPC	Jo Daviess	115 min
Jun 5, 7:59 AM CDT	Mesoscale Discussion	SPC	Adams, Brown, Hancock, Henderson, McDonough, Pike and 1 more	91 min
Jun 4, 11:32 PM CDT	Severe Thunderstorm Watch	SPC	Fremont, Mills, Montgomery, Page	7 hr
Jun 5, 1:02 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Allamakee, Appanoose, Audubon, Benton, Black Hawk and 54 more	6 hr
Jun 5, 1:59 AM CDT	Mesoscale Discussion	SPC	Adams, Fremont, Mills, Montgomery, Page, Ringgold and 1 more	91 min
Jun 5, 4:17 AM CDT	Mesoscale Discussion	SPC	Appanoose, Benton, Black Hawk, Boone, Bremer, Buchanan and 34 more	88 min

Nearby

Mesoscale Discussions in Illinois, 2020 Mesoscale Discussions in Wisconsin, 2020 Mesoscale Discussions in Michigan, 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.