Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1293
The Storm Prediction Center issued this mesoscale discussion at Jul 15, 2021, 1:39 PM CDT for 30 counties in Illinois; 18 counties in Indiana. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 15, 2021, 1:39 PM CDT (18:39 UTC)
- Expired
- Jul 15, 2021, 3:45 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 48 counties
Brown County, IL, Cass County, IL, Champaign County, IL, Christian County, IL, Coles County, IL, DeWitt County, IL, Douglas County, IL, Edgar County, IL, Ford County, IL, Fulton County, IL, Iroquois County, IL, Kankakee County, IL, Livingston County, IL, Logan County, IL, Macon County, IL, Mason County, IL, McDonough County, IL, McLean County, IL, Menard County, IL, Morgan County, IL, Moultrie County, IL, Piatt County, IL, Pike County, IL, Sangamon County, IL, Schuyler County, IL, Scott County, IL, Shelby County, IL, Tazewell County, IL, Vermilion County, IL, Woodford County, IL, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, Fountain County, IN, Hendricks County, IN, Howard County, IN, Jasper County, IN, Montgomery County, IN, Newton County, IN, Parke County, IN, Pulaski County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Warren County, IN, White County, IN
The radar
The Lincoln radar (KILX), 48 km from the middle of the area, began a volume at 18:40 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 18 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
- 628 J/kg
- Mixed-layer CIN
- -48 J/kg
- Mixed-layer LCL
- 1096 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 217 m²/s²
- 0-3 km storm-relative helicity
- 188 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 2.6
The text
As transmitted.
424
ACUS11 KWNS 151840
SWOMCD
SPC MCD 151839
INZ000-ILZ000-152045-
Mesoscale Discussion 1293
NWS Storm Prediction Center Norman OK
0139 PM CDT Thu Jul 15 2021
Areas affected...central Illinois into Indiana
Concerning...Severe potential...Watch possible
Valid 151839Z - 152045Z
Probability of Watch Issuance...40 percent
SUMMARY...Storms are likely to increase in coverage, with localized
wind damage possible. A watch could be needed if it becomes apparent
severe will be more widespread than currently anticipated.
DISCUSSION...A small cluster of storms is showing increasing trends
as it crossed from northeast MO into western IL, while smaller
showers are also forming over southern and eastern IL.
Visible satellite shows strong heating from southeast MO across IL
and into IN, with widespread high clouds across northern MO and IL.
Objective analysis indicates up to 2000 J/kg MLCAPE in the
well-heated areas, with the instability gradient aligned along the
southern edge of the thicker high clouds. Mean winds through a deep
layer are out of the west/southwest at around 30 kt, which will
provide favorable storm-relative inflow to any developing clusters.
The favorable time of day along with PWAT over 1.50" suggests a few
downdrafts may be substantial. Thus, at least isolated damaging
gusts appear likely as activity increases in intensity and coverage
over the next several hours.
..Jewell/Bunting.. 07/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN...
LAT...LON 39689116 40149120 40519077 41308721 41198654 40818618
40338604 39838627 39378793 39298894 39358993 39439078
39689116SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 9:15 PM CDT | Mesoscale Discussion | SPC | Carroll, Jo Daviess, Ogle, Stephenson, Winnebago | 90 min |
| Jul 14, 11:17 PM CDT | Mesoscale Discussion | SPC | Boone, Carroll, DeKalb, Henry, Lee, McHenry and 6 more | 58 min |
| Jul 14, 11:57 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Bureau, DeKalb, Grundy, Henry, Kane and 7 more | 3 hr |
| Jul 15, 2:14 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, DeKalb, DuPage, Grundy, Kane and 12 more | 61 min |
Nearby
Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Indiana, 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.