Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1892
The Storm Prediction Center issued this mesoscale discussion at Oct 24, 2021, 5:11 PM CDT for 45 counties in Illinois; Vermillion County, Warren County, Indiana; Saint Louis County, City of Saint Louis, Missouri. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Oct 24, 2021, 5:11 PM CDT (22:11 UTC)
- Expired
- Oct 24, 2021, 7:45 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 49 counties
Bond County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Effingham County, IL, Fayette County, IL, Ford County, IL, Greene County, IL, Iroquois County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Monroe County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Perry County, IL, Piatt County, IL, Pike County, IL, Randolph County, IL, Saint Clair County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Washington County, IL, Vermillion County, IN, Warren County, IN, City of Saint Louis, MO, Saint Louis County, MO
The radar
The Lincoln radar (KILX), 53 km from the middle of the area, began a volume at 22:12 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
Davenport, (KDVN), launched 12:00Z, 10.2 hours before the alert went out and 243 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 972 m above ground
- 0-6 km bulk shear
- 61 kt
- 0-1 km storm-relative helicity
- 120 m²/s²
- 0-3 km storm-relative helicity
- 162 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
434
ACUS11 KWNS 242211
SWOMCD
SPC MCD 242211
INZ000-ILZ000-MOZ000-250045-
Mesoscale Discussion 1892
NWS Storm Prediction Center Norman OK
0511 PM CDT Sun Oct 24 2021
Areas affected...much of central and southwestern Illinois
Concerning...Severe potential...Watch likely
Valid 242211Z - 250045Z
Probability of Watch Issuance...80 percent
SUMMARY...Severe storms including damaging wind and tornadoes are
possible along the warm front into central Illinois, and with other
storms forming along and ahead of the cold front later this evening
into southern Illinois and vicinity.
DISCUSSION...A line of storms currently straddles the warm front,
extending from northern IL into northeast MO. Southern parts of this
line near Pike County MO are showing signs of organization and
rotation, and are close to the warm front. A moist and unstable air
mass exists near this boundary, and favorably strong shear may
result in damaging winds and tornadoes as it treks east/northeast
where 0-1 SRH exceed 200 m2/s2. To the northeast, parts of
east/northeast IL may experience destabilization later this evening
as the low levels jet continues to mix the boundary layer. Farther
south, a pre-frontal band of storms over south-central MO may
eventually become better organized with shear favoring supercells
and/or QLCS structures.
..Jewell/Hart.. 10/24/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IND...PAH...LOT...ILX...LSX...
LAT...LON 39878736 38608821 37938947 37928984 38309034 39229085
39549096 39859081 40289014 40638953 40958859 41048807
40948764 40798748 40318736 39878736SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 23, 9:14 PM CDT | Mesoscale Discussion | SPC | Adams, Hancock | 3 hr |
| Oct 24, 2:13 AM CDT | Mesoscale Discussion | SPC | Calhoun, Greene | 2 hr |
| Oct 24, 12:40 PM CDT | Mesoscale Discussion | SPC | Calhoun, Jersey | 3 hr |
| Oct 24, 2:06 PM CDT | Tornado Watch | SPC | Adams, Brown, Calhoun, Greene, Jersey, Pike | 9 hr |
| Oct 24, 5:44 PM CDT | Tornado Watch | SPC | Alexander, Bond, Cass, Champaign, Christian, Clark and 47 more | 7 hr |
| Oct 23, 9:53 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Andrew, Atchison, Buchanan, Caldwell, Carroll and 24 more | 7 hr |
| Oct 24, 3:28 PM CDT | Mesoscale Discussion | SPC | Bates, Caldwell, Carroll, Cass, Daviess, Grundy and 10 more | 92 min |
| Oct 24, 3:50 PM CDT | Mesoscale Discussion | SPC | Audrain, Callaway, Cole, Franklin, Gasconade, Lincoln and 8 more | 85 min |
| Oct 24, 5:25 PM CDT | Mesoscale Discussion | SPC | Adair, Audrain, Benton, Boone, Callaway, Camden and 41 more | 2 hr |
Nearby
Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Missouri, 2021Every mesoscale discussion in 2021
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.