Alert archive / Illinois / Mesoscale Discussions in 2018

Mesoscale Discussion 974

July 1, 201862 counties in Illinois

The Storm Prediction Center issued this mesoscale discussion at Jul 1, 2018, 12:23 PM CDT for 62 counties in Illinois. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Jul 1, 2018, 12:23 PM CDT (17:23 UTC)
Expired: Jul 1, 2018, 2:00 PM CDT
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 80%

All 62 counties

Adams County, IL, Bond County, IL, Boone County, IL, Brown County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, Douglas County, IL, DuPage County, IL, Fayette County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Henderson County, IL, Henry County, IL, Iroquois County, IL, Jersey 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, Logan County, IL, Macon County, IL, Macoupin County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McHenry County, IL, McLean County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Vermilion County, IL, Warren County, IL, Whiteside County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 98 km from the middle of the area, began a volume at 17:23 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 253Jul 1, 1:00 PM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 5.4 hours before the alert went out and 112 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: 1834 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 867 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 123 m²/s²
0-3 km storm-relative helicity: 109 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.5

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 1, 11:37 AM CDT	Mesoscale Discussion	SPC	Boone, Jo Daviess, McHenry, Stephenson, Winnebago	83 min
Jul 1, 12:58 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Boone, Bureau, Cass, Champaign, Christian and 49 more	7 hr
Jul 1, 3:37 PM CDT	Mesoscale Discussion	SPC	Bond, Boone, Cass, Champaign, Christian, Clark and 46 more	83 min
Jul 1, 6:51 PM CDT	Mesoscale Discussion	SPC	Bond, Champaign, Christian, Clark, Clay, Clinton and 22 more	114 min

Nearby

Mesoscale Discussions in Illinois, 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.