Alert archive / Missouri / Mesoscale Discussions in 2021

Mesoscale Discussion 1458

August 10, 202115 counties in Illinois; 24 counties in Missouri

The Storm Prediction Center issued this mesoscale discussion at Aug 10, 2021, 10:45 AM CDT for 15 counties in Illinois; 24 counties in Missouri. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Aug 10, 2021, 10:45 AM CDT (15:45 UTC)
Expired: Aug 10, 2021, 1:15 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

All 39 counties

Adams County, IL, Bond County, IL, Brown County, IL, Calhoun County, IL, Clinton County, IL, Greene County, IL, Jersey County, IL, Macoupin County, IL, Madison County, IL, Montgomery County, IL, Morgan County, IL, Pike County, IL, Saint Clair County, IL, Scott County, IL, Washington County, IL, Audrain County, MO, Boone County, MO, Callaway County, MO, Chariton County, MO, City of Saint Louis, MO, Cooper County, MO, Franklin County, MO, Howard County, MO, Knox County, MO, Lewis County, MO, Lincoln County, MO, Macon County, MO, Marion County, MO, Moniteau County, MO, Monroe County, MO, Montgomery County, MO, Pike County, MO, Ralls County, MO, Randolph County, MO, Saint Charles County, MO, Saint Louis County, MO, Saline County, MO, Shelby County, MO, Warren County, MO

The radar

The St Louis radar (KLSX), 101 km from the middle of the area, began a volume at 15:47 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, 3.8 hours before the alert went out and 279 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 3933 J/kg
Mixed-layer CIN: -32 J/kg
Mixed-layer LCL: 851 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -53 m²/s²
0-3 km storm-relative helicity: -47 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.

Issued	Product	Office	Counties	Lasted
Aug 9, 8:33 PM CDT	Mesoscale Discussion	SPC	Bureau, Knox, LaSalle, Livingston, Marshall, Peoria and 4 more	87 min
Aug 10, 2:08 PM CDT	Severe Thunderstorm Watch	SPC	Henderson, Mercer, Rock Island, Warren	6 hr
Aug 10, 2:20 PM CDT	Mesoscale Discussion	SPC	Alexander, Bond, Clay, Clinton, Edwards, Franklin and 21 more	2 hr
Aug 10, 3:10 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, DeKalb, Jo Daviess, Kane, Lake and 6 more	2 hr
Aug 10, 3:47 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 15 more	6 hr
Aug 10, 5:51 PM CDT	Mesoscale Discussion	SPC	Boone, Carroll, DeKalb, DuPage, Jo Daviess, Kane and 7 more	84 min

Nearby

Mesoscale Discussions in Missouri, 2021 Mesoscale Discussions in Illinois, 2021 Every 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.