Alert archive / Illinois / Mesoscale Discussions in 2017
Mesoscale Discussion 1544
The Storm Prediction Center issued this mesoscale discussion at Aug 21, 2017, 3:29 PM CDT for 28 counties in Illinois; Gibson County, Knox County, Sullivan County, Indiana; 6 counties in Missouri. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Aug 21, 2017, 3:29 PM CDT (20:29 UTC)
- Expired
- Aug 21, 2017, 5:00 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 37 counties
Bond County, IL, Calhoun County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Greene County, IL, Hamilton County, IL, Jasper County, IL, Jefferson County, IL, Jersey County, IL, Lawrence County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Montgomery County, IL, Richland County, IL, Saint Clair County, IL, Shelby County, IL, Wabash County, IL, Washington County, IL, Wayne County, IL, White County, IL, Gibson County, IN, Knox County, IN, Sullivan County, IN, City of Saint Louis, MO, Lincoln County, MO, Pike County, MO, Saint Charles County, MO, Saint Louis County, MO, Warren County, MO
The radar
The St Louis radar (KLSX), 97 km from the middle of the area, began a volume at 20:32 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, 8.5 hours before the alert went out and 168 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
- 1645 J/kg
- Mixed-layer CIN
- -103 J/kg
- Mixed-layer LCL
- 992 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 85 m²/s²
- 0-3 km storm-relative helicity
- 117 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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 |
|---|---|---|---|---|
| Aug 21, 12:41 PM CDT | Mesoscale Discussion | SPC | Clark, Coles, Crawford, Cumberland, Edgar, Effingham and 3 more | 94 min |
| Aug 21, 3:41 PM CDT | Mesoscale Discussion | SPC | Audrain, Boone, Callaway, Carroll, Cass, Chariton and 13 more | 94 min |
| Aug 21, 6:36 PM CDT | Mesoscale Discussion | SPC | Bates, Benton, Boone, Buchanan, Caldwell, Callaway and 17 more | 114 min |
Nearby
Mesoscale Discussions in Illinois, 2017Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Indiana, 2017Every mesoscale discussion in 2017
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.