Alert archive / Illinois / Mesoscale Discussions in 2017

Mesoscale Discussion 1423

July 26, 201748 counties in Illinois; 8 counties in Iowa

The Storm Prediction Center issued this mesoscale discussion at Jul 26, 2017, 4:55 PM CDT for 48 counties in Illinois; 8 counties in Iowa. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Jul 26, 2017, 4:55 PM CDT (21:55 UTC)
Expired: Jul 26, 2017, 6:00 PM CDT
In force: 65 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 56 counties

Cedar County, IA, Clinton County, IA, Des Moines County, IA, Jackson County, IA, Jones County, IA, Louisa County, IA, Muscatine County, IA, Scott County, IA, Brown County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, DeKalb County, IL, DeWitt County, IL, Ford County, IL, Fulton County, IL, Greene County, IL, Grundy County, IL, Hancock County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Kane County, IL, Kendall County, IL, Knox County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Mercer County, IL, Morgan County, IL, Moultrie County, IL, Ogle County, IL, Peoria County, IL, Piatt County, IL, Pike County, IL, Putnam County, IL, Rock Island County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL, Woodford County, IL

The radar

The Quad Cities radar (KDVN), 84 km from the middle of the area, began a volume at 21:58 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 9.9 hours before the alert went out and 421 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: 4 J/kg
Mixed-layer CIN: -378 J/kg
Mixed-layer LCL: 1064 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 222 m²/s²
0-3 km storm-relative helicity: 221 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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Nearby

Mesoscale Discussions in Illinois, 2017 Mesoscale Discussions in Iowa, 2017 Every mesoscale discussion in 2017

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.