Alert archive / Illinois / Mesoscale Discussions in 2021

Mesoscale Discussion 1181

July 7, 20216 states

The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2021, 2:02 PM CDT for 6 states. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jul 7, 2021, 2:02 PM CDT (19:02 UTC)
Expired: Jul 7, 2021, 3:30 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 20%

All 54 counties

Des Moines County, IA, Henry County, IA, Lee County, IA, Louisa County, IA, Boone County, IL, Bureau County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Ford County, IL, Fulton County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Knox County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Mercer County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Rock Island County, IL, Stark County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Benton County, IN, Jasper County, IN, Lake County, IN, LaPorte County, IN, Newton County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, White County, IN, Berrien County, MI, Clark County, MO, Rock County, WI, Walworth County, WI

The radar

The Chicago radar (KLOT), 61 km from the middle of the area, began a volume at 19:02 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

Lincoln, IL (KILX), launched 12:00Z, 7.0 hours before the alert went out and 140 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: 142 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 1432 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 23 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Jul 7, 11:07 AM CDT	Mesoscale Discussion	SPC	Adams, Allen, DeKalb, Elkhart, Huntington, LaGrange and 4 more	83 min
Jul 7, 12:31 PM CDT	Severe Thunderstorm Watch	SPC	Allen, DeKalb, Elkhart, Kosciusko, LaGrange, Noble and 2 more	7 hr
Jul 7, 2:59 PM CDT	Mesoscale Discussion	SPC	Allen, DeKalb, Elkhart, LaGrange, Noble, Steuben	91 min
Jul 6, 8:00 PM CDT	Mesoscale Discussion	SPC	Howard, Mitchell, Winnebago, Winneshiek, Worth	2 hr

Nearby

Mesoscale Discussions in Illinois, 2021 Mesoscale Discussions in Indiana, 2021 Mesoscale Discussions in Iowa, 2021 Every mesoscale discussion in 2021

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.