Alert archive / Illinois / Mesoscale Discussions in 2018

Mesoscale Discussion 372

May 9, 201825 counties in Illinois; 7 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 9, 2018, 3:50 PM CDT for 25 counties in Illinois; 7 counties in Wisconsin. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 9, 2018, 3:50 PM CDT (20:50 UTC)
Expired: May 9, 2018, 5:15 PM CDT
In force: 85 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 32 counties

Boone County, IL, Cook County, IL, DeKalb County, IL, DeWitt County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, McHenry County, IL, McLean County, IL, Ogle County, IL, Putnam County, IL, Tazewell County, IL, Will County, IL, Winnebago County, IL, Woodford County, IL, Dane County, WI, Green County, WI, Jefferson County, WI, Kenosha County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI

The radar

The Chicago radar (KLOT), 48 km from the middle of the area, began a volume at 20:50 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, 8.8 hours before the alert went out and 175 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1485 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 347 m²/s²
0-3 km storm-relative helicity: 285 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
May 9, 1:49 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Bureau, Carroll, Cass, Fulton and 16 more	116 min

Nearby

Mesoscale Discussions in Illinois, 2018 Mesoscale Discussions in Wisconsin, 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.