Alert archive / Illinois / Mesoscale Discussions in 2020
Mesoscale Discussion 1302
The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2020, 1:43 PM CDT for 23 counties in Illinois; 10 counties in Missouri. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Jul 21, 2020, 1:43 PM CDT (18:43 UTC)
- Expired
- Jul 21, 2020, 3:15 PM CDT
- In force
- 92 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 33 counties
Bond County, IL, Calhoun County, IL, Cass County, IL, Christian County, IL, Clinton County, IL, Coles County, IL, Cumberland County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Jersey County, IL, Macon County, IL, Macoupin County, IL, Madison County, IL, Menard County, IL, Montgomery County, IL, Morgan County, IL, Moultrie County, IL, Pike County, IL, Saint Clair County, IL, Sangamon County, IL, Scott County, IL, Shelby County, IL, Audrain County, MO, City of Saint Louis, MO, Franklin County, MO, Lincoln County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO
The radar
The St Louis radar (KLSX), 70 km from the middle of the area, began a volume at 18:45 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, 6.7 hours before the alert went out and 171 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
- 474 J/kg
- Mixed-layer CIN
- -67 J/kg
- Mixed-layer LCL
- 804 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 57 m²/s²
- 0-3 km storm-relative helicity
- 138 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 11:19 AM CDT | Mesoscale Discussion | SPC | Champaign, Clark, Coles, Cumberland, DeWitt, Douglas and 12 more | 86 min |
| Jul 21, 5:04 PM CDT | Mesoscale Discussion | SPC | Bond, Champaign, Christian, Clark, Clay, Clinton and 24 more | 56 min |
Nearby
Mesoscale Discussions in Illinois, 2020Mesoscale Discussions in Missouri, 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.