Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1096
The Storm Prediction Center issued this mesoscale discussion at Jun 25, 2021, 4:46 PM CDT for 29 counties in Illinois; 20 counties in Missouri. It was in force for 59 min.
The area
The outline as issued.
The facts
- Issued
- Jun 25, 2021, 4:46 PM CDT (21:46 UTC)
- Expired
- Jun 25, 2021, 5:45 PM CDT
- In force
- 59 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...severe thunderstorm watch likely
- Chance of a watch
- 80%
All 49 counties
Bond County, IL, Brown County, IL, Calhoun County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Logan County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Mason County, IL, McLean County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Pike County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, City of Saint Louis, MO, Cole County, MO, Franklin County, MO, Gasconade County, MO, Lincoln County, MO, Marion County, MO, Miller County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Osage County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO
The radar
The St Louis radar (KLSX), 67 km from the middle of the area, began a volume at 21:49 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 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, 9.8 hours before the alert went out and 203 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
- 1244 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 113 m²/s²
- 0-3 km storm-relative helicity
- 257 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
482 ACUS11 KWNS 252146 SWOMCD SPC MCD 252146 ILZ000-MOZ000-252245- Mesoscale Discussion 1096 NWS Storm Prediction Center Norman OK 0446 PM CDT Fri Jun 25 2021 Areas affected...central Missouri to central Illinois Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 252146Z - 252245Z Probability of Watch Issuance...80 percent SUMMARY...Severe thunderstorm watch appears warranted to account for expected upscale convective growth over the next several hours. DISCUSSION...Despite earlier MCS that spread across the Midwest, rapid air mass destabilization is occurring just southwest of the STL area. Further destabilization is expected downstream across central IL over the next few hours which should contribute to robust convection. Latest satellite imagery exhibits a line of deepening cumulus, with some showers, from near SPI to north of CMI. Thunderstorms will likely evolve along this corridor soon. Additionally, larger cluster of strong/severe storms should propagate across central into eastern MO with a threat for hail/wind. WW will likely be issued soon. ..Darrow/Grams.. 06/25/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...LSX...SGF...EAX... LAT...LON 39549270 40748829 39388781 38439003 38169268 39549270
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 24, 8:57 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Hancock, Pike | 6 hr |
| Jun 24, 11:23 PM CDT | Mesoscale Discussion | SPC | Adams, Brown, Calhoun, Cass, Greene, Hancock and 9 more | 2 hr |
| Jun 24, 11:47 PM CDT | Tornado Watch | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 18 more | 4 hr |
| Jun 25, 12:57 PM CDT | Mesoscale Discussion | SPC | Alexander, Clay, Crawford, Edwards, Franklin, Gallatin and 15 more | 2 hr |
| Jun 25, 5:06 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Brown, Calhoun, Cass, Champaign, Christian and 30 more | 6 hr |
| Jun 25, 6:47 PM CDT | Severe Thunderstorm Watch | SPC | Kankakee | 4 hr |
| Jun 24, 7:29 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Buchanan, DeKalb, Gentry, Harrison and 4 more | 61 min |
| Jun 24, 8:33 PM CDT | Mesoscale Discussion | SPC | Adair, Andrew, Audrain, Bates, Benton, Boone and 49 more | 87 min |
| Jun 25, 11:56 AM CDT | Mesoscale Discussion | SPC | Bates, Benton, Cass, Cedar, Dade, Dallas and 8 more | 3 hr |
| Jun 25, 1:43 PM CDT | Severe Thunderstorm Watch | SPC | Barton, Bates, Benton, Carroll, Cass, Cedar and 14 more | 9 hr |
| Jun 25, 3:13 PM CDT | Mesoscale Discussion | SPC | Bates, Benton, Camden, Cass, Henry, Hickory and 7 more | 2 hr |
| Jun 25, 6:21 PM CDT | Mesoscale Discussion | SPC | Bates, Henry, Hickory, St. Clair, Vernon | 84 min |
Nearby
Mesoscale Discussions in Illinois, 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.