Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1447
The Storm Prediction Center issued this mesoscale discussion at Aug 8, 2021, 5:47 PM CDT for 33 counties in Illinois; Ballard County, Kentucky; 5 counties in Missouri. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Aug 8, 2021, 5:47 PM CDT (22:47 UTC)
- Expired
- Aug 8, 2021, 7:15 PM CDT
- In force
- 88 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 415
All 39 counties
Alexander County, IL, Bond County, IL, Champaign County, IL, Christian County, IL, Clay County, IL, Clinton County, IL, Coles County, IL, Cumberland County, IL, DeWitt County, IL, Douglas County, IL, Effingham County, IL, Fayette County, IL, Franklin County, IL, Hamilton County, IL, Jackson County, IL, Jasper County, IL, Jefferson County, IL, Johnson County, IL, Logan County, IL, Macon County, IL, Marion County, IL, Montgomery County, IL, Moultrie County, IL, Perry County, IL, Piatt County, IL, Pulaski County, IL, Richland County, IL, Saline County, IL, Shelby County, IL, Union County, IL, Washington County, IL, Wayne County, IL, Williamson County, IL, Ballard County, KY, Cape Girardeau County, MO, Mississippi County, MO, New Madrid County, MO, Scott County, MO, Stoddard County, MO
The radar
The Evansville,IN radar (KVWX), 127 km from the middle of the area, began a volume at 22:47 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, 10.8 hours before the alert went out and 189 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
- 310 J/kg
- Mixed-layer CIN
- -97 J/kg
- Mixed-layer LCL
- 1165 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- -3 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
784
ACUS11 KWNS 082248
SWOMCD
SPC MCD 082247
ILZ000-KYZ000-MOZ000-090015-
Mesoscale Discussion 1447
NWS Storm Prediction Center Norman OK
0547 PM CDT Sun Aug 08 2021
Areas affected...Parts of central and southern
Ilinois...southeastern Missouri and portions of adjacent western
Kentucky
Concerning...Severe Thunderstorm Watch 415...
Valid 082247Z - 090015Z
The severe weather threat for Severe Thunderstorm Watch 415
continues.
SUMMARY...A line of strong thunderstorms may continue to pose at
least some risk for localized strong to severe wind gusts as it
progresses across much of the remainder of central and southern
Illinois, and adjacent portions of southeastern Missouri and western
Kentucky, through 7-9 PM CDT. A new severe weather watch is not
anticipated, but trends will continue to be monitored.
DISCUSSION...Ongoing line of storms is maintaining at least modest
intensity, as it generally advects east-northeastward within 20-30
kt deep-layer southwesterly mean ambient flow, ahead of a mid-level
short wave trough progressing into the middle Mississippi Valley.
There remains a corridor of seasonably moist and modestly heated
boundary-layer air characterized by CAPE in excess of 2000 J/kg
ahead of activity. However, vertical shear is weak enough to allow
convective outflow to begin advancing ahead of the more intense
leading line of convection, particularly areas from near Perryville,
MO northward. Substantive further intensification of storms does
not appear likely, but activity might still remain capable of
generating locally strong, potentially damaging, wind gusts into the
00-02Z time frame, before diminishing.
..Kerr.. 08/08/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...LOT...ILX...MEG...LSX...
LAT...LON 36799037 37628972 38478950 39148954 40158945 40278898
40408846 40658788 39858785 38628806 37388857 36588935
36369003 36799037SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 11:40 AM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 18 more | 3 hr |
| Aug 8, 12:44 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more | 7 hr |
| Aug 8, 3:00 PM CDT | Mesoscale Discussion | SPC | Adams, Bond, Brown, Calhoun, Cass, Christian and 36 more | 2 hr |
| Aug 7, 9:35 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Buchanan, Caldwell, Clay, Clinton and 8 more | 85 min |
| Aug 7, 11:19 PM CDT | Mesoscale Discussion | SPC | Andrew, Atchison, Gentry, Holt, Nodaway, Worth | 86 min |
Nearby
Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Missouri, 2021Mesoscale Discussions in Kentucky, 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.