Alert archive / Illinois / Mesoscale Discussions in 2026

Mesoscale Discussion 565

April 27, 202630 counties in Illinois; Ballard County, McCracken County, Kentucky; 23 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2026, 7:36 AM CDT for 30 counties in Illinois; Ballard County, McCracken County, Kentucky; 23 counties in Missouri. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2026, 7:36 AM CDT (12:36 UTC)
Expired
Apr 27, 2026, 9:00 AM CDT
In force
84 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 156...157
All 55 counties

Adams County, IL, Alexander County, IL, Bond County, IL, Calhoun County, IL, Clinton County, IL, Franklin County, IL, Gallatin County, IL, Greene County, IL, Hamilton County, IL, Jackson County, IL, Jefferson County, IL, Jersey County, IL, Johnson County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Massac County, IL, Monroe County, IL, Perry County, IL, Pike County, IL, Pope County, IL, Pulaski County, IL, Randolph County, IL, Saint Clair County, IL, Saline County, IL, Union County, IL, Washington County, IL, Wayne County, IL, White County, IL, Williamson County, IL, Ballard County, KY, McCracken County, KY, Audrain County, MO, Boone County, MO, Callaway County, MO, Cape Girardeau County, MO, City of Saint Louis, MO, Cole County, MO, Franklin County, MO, Gasconade County, MO, Jefferson County, MO, Lincoln County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Perry County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shelby County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 3 km from the middle of the area, began a volume at 12:39 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 12:00Z, 0.6 hours before the alert went out and 239 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 2026-04-27Temperature 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 2026-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 104 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
1053 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
104 m²/s²
0-3 km storm-relative helicity
306 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
Apr 27, 4:07 AM CDTSevere Thunderstorm WatchSPCAlexander, Calhoun, Edwards, Franklin, Gallatin, Greene and 21 more6 hr
Apr 27, 8:31 AM CDTSevere Thunderstorm WatchSPCAdams, Bond, Brown, Cass, Champaign, Christian and 37 more5 hr
Apr 27, 9:33 AM CDTMesoscale DiscussionSPCCalhoun117 min
Apr 27, 10:31 AM CDTMesoscale DiscussionSPCBond, Champaign, Christian, Clark, Clay, Clinton and 35 more119 min
Apr 27, 11:12 AM CDTSevere Thunderstorm WatchSPCWabash8 hr
Apr 27, 11:56 AM CDTMesoscale DiscussionSPCCalhoun, Jersey, Macoupin, Madison, Monroe, Saint Clair2 hr
Apr 27, 12:50 PM CDTTornado WatchSPCBond, Calhoun, Clinton, Edwards, Fayette, Franklin and 17 more9 hr
Apr 27, 12:51 PM CDTTornado WatchSPCChampaign, Christian, Clark, Clay, Coles, Crawford and 15 more4 hr
Apr 27, 1:44 PM CDTMesoscale DiscussionSPCAlexander, Gallatin, Hardin, Jackson, Johnson, Massac and 5 more2 hr
Apr 27, 2:46 PM CDTTornado Watch PDSSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more7 hr
Apr 27, 3:55 PM CDTMesoscale DiscussionSPCBond, Calhoun, Clinton, Fayette, Greene, Jersey and 5 more2 hr
Apr 27, 3:58 PM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 11 more92 min
Apr 27, 4:41 PM CDTTornado WatchSPCCass, Champaign, Christian, Clark, Clay, Coles and 20 more6 hr
Apr 27, 6:18 PM CDTMesoscale DiscussionSPCAlexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 9 more87 min
Apr 27, 1:37 PM CDTMesoscale DiscussionSPCJefferson, Meade, Oldham, Trimble113 min
Apr 27, 5:26 PM CDTMesoscale DiscussionSPCBreckinridge, Bullitt, Carroll, Hardin, Henry, Jefferson and 6 more2 hr
Apr 26, 7:40 PM CDTMesoscale DiscussionSPCMcDonald, Newton65 min
Apr 26, 8:38 PM CDTMesoscale DiscussionSPCAndrew, Buchanan, Clay, Clinton, DeKalb, Gentry and 3 more2 hr
Apr 26, 9:11 PM CDTSevere Thunderstorm WatchSPCAndrew, Bates, Buchanan, Carroll, Cass, Clay and 11 more7 hr
Apr 26, 10:22 PM CDTMesoscale DiscussionSPCBarry, Barton, Cedar, Christian, Dade, Dallas and 18 more113 min
Apr 26, 10:56 PM CDTMesoscale DiscussionSPCMcDonald94 min
Apr 27, 12:50 AM CDTMesoscale DiscussionSPCCrawford, Dent, Franklin, Gasconade, Iron, Osage and 3 more55 min
Apr 27, 1:39 AM CDTMesoscale DiscussionSPCCass, Clay, Jackson, Platte96 min
Apr 27, 3:24 AM CDTMesoscale DiscussionSPCCaldwell, Carroll, Cass, Chariton, Clay, Clinton and 13 more96 min
Apr 27, 3:46 AM CDTSevere Thunderstorm WatchSPCBates, Benton, Buchanan, Caldwell, Carroll, Cass and 21 more6 hr
Apr 27, 5:59 AM CDTMesoscale DiscussionSPCCass, Cooper, Johnson, Lafayette, Pettis, Saline91 min
Apr 27, 1:55 PM CDTMesoscale DiscussionSPCBarry, Barton, Bates, Cass, Cedar, Dade and 7 more95 min
Apr 27, 2:07 PM CDTSevere Thunderstorm WatchSPCBarry, Barton, Bates, Cass, Cedar, Cooper and 14 more7 hr

Nearby

Mesoscale Discussions in Illinois, 2026Mesoscale Discussions in Missouri, 2026Mesoscale Discussions in Kentucky, 2026Every mesoscale discussion in 2026

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.