Alert archive / Illinois / Mesoscale Discussions in 2018

Mesoscale Discussion 371

May 9, 201822 counties in Illinois; Green County, Iowa County, Lafayette County, Wisconsin

The Storm Prediction Center issued this mesoscale discussion at May 9, 2018, 1:49 PM CDT for 22 counties in Illinois; Green County, Iowa County, Lafayette County, Wisconsin. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued
May 9, 2018, 1:49 PM CDT (18:49 UTC)
Expired
May 9, 2018, 3:45 PM CDT
In force
116 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 25 counties

Adams County, IL, Brown County, IL, Bureau County, IL, Carroll County, IL, Cass County, IL, Fulton County, IL, Henry County, IL, Jo Daviess County, IL, Knox County, IL, Lee County, IL, Marshall County, IL, Mason County, IL, McDonough County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Schuyler County, IL, Stark County, IL, Stephenson County, IL, Tazewell County, IL, Warren County, IL, Whiteside County, IL, Green County, WI, Iowa County, WI, Lafayette County, WI

The radar

The Quad Cities radar (KDVN), 69 km from the middle of the area, began a volume at 18:49 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, 6.8 hours before the alert went out and 166 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-pSkew-T log-p diagram, Lincoln, IL at 12:00Z on 2018-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lincoln, IL at 12:00Z on 2018-05-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 347 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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.

IssuedProductOfficeCountiesLasted
May 9, 3:50 PM CDTMesoscale DiscussionSPCBoone, Cook, DeKalb, DeWitt, DuPage, Ford and 19 more85 min

Nearby

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