Alert archive / Illinois / Mesoscale Discussions in 2020

Mesoscale Discussion 261

March 28, 202023 counties in Illinois

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2020, 8:06 PM CDT for 23 counties in Illinois. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Mar 28, 2020, 8:06 PM CDT (01:06 UTC)
Expired
Mar 28, 2020, 9:00 PM CDT
In force
54 min
Issued by
the Storm Prediction Center
All 23 counties

Bureau County, IL, Carroll County, IL, Cass County, IL, DeKalb County, IL, DeWitt County, IL, Grundy County, IL, Kendall County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Logan County, IL, Marshall County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Ogle County, IL, Peoria County, IL, Putnam County, IL, Stark County, IL, Tazewell County, IL, Whiteside County, IL, Woodford County, IL

The radar

The Lincoln radar (KILX), 76 km from the middle of the area, began a volume at 01:07 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.1 hours before the alert went out and 108 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 00:00Z on 2020-03-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 730 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2020-03-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 445 square meters per square second.1939587897117136Sfc1 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
730 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
861 m above ground
0-6 km bulk shear
81 kt
0-1 km storm-relative helicity
445 m²/s²
0-3 km storm-relative helicity
445 m²/s²
Significant tornado parameter
2.2
Supercell composite
15.8

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
Mar 28, 8:41 PM CDTTornado WatchSPCBureau, Cass, Champaign, Christian, DeKalb, DeWitt and 27 more3 hr
Mar 28, 10:23 PM CDTMesoscale DiscussionSPCDeKalb, Ford, Grundy, Kendall, LaSalle, Livingston and 1 more97 min

Nearby

Mesoscale Discussions in Illinois, 2020Every mesoscale discussion in 2020

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.