Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1292
The Storm Prediction Center issued this mesoscale discussion at Jul 15, 2021, 2:14 AM CDT for 18 counties in Illinois. It was in force for 61 min.
The area
The outline as issued.
The facts
- Issued
- Jul 15, 2021, 2:14 AM CDT (07:14 UTC)
- Expired
- Jul 15, 2021, 3:15 AM CDT
- In force
- 61 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 380
Counties Boone County, IL, Bureau County, IL, DeKalb County, IL, DuPage County, IL, Grundy County, IL, Kane County, IL, Kankakee County, IL, Kendall County, IL, Lake County, IL, LaSalle County, IL, Lee County, IL, Livingston County, IL, Marshall County, IL, McHenry County, IL, Ogle County, IL, Putnam County, IL, Stark County, IL, Will County, IL
The radar
The Chicago radar (KLOT), 63 km from the middle of the area, began a volume at 07:17 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
Davenport, (KDVN), launched 00:00Z, 7.2 hours before the alert went out and 139 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
- 2569 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 832 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 253 m²/s²
- 0-3 km storm-relative helicity
- 346 m²/s²
- Significant tornado parameter
- 3.2
- Supercell composite
- 23.4
The text
As transmitted.
465
ACUS11 KWNS 150715
SWOMCD
SPC MCD 150714
ILZ000-WIZ000-150815-
Mesoscale Discussion 1292
NWS Storm Prediction Center Norman OK
0214 AM CDT Thu Jul 15 2021
Areas affected...northern Illinois
Concerning...Severe Thunderstorm Watch 380...
Valid 150714Z - 150815Z
The severe weather threat for Severe Thunderstorm Watch 380
continues.
SUMMARY...The overall thunderstorm intensity continues to wane.
However, gusty thunderstorm winds capable of sporadic tree damage
may continue for another couple of hours.
DISCUSSION...Thunderstorm intensity continues to decrease across
northern Illinois as the nocturnal boundary layer deepens and,
consequently, low-level buoyancy weakens. Although gusty
thunderstorm winds on the leading edge of the convective line may
yield sporadic tree damage, the potential for a more organized wind
threat is diminishing.
..Marsh.. 07/15/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LOT...ILX...MKX...DVN...
LAT...LON 41049047 42058936 42638833 42418778 41688759 41068759
40898851 40938944 41049047SPC 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, 1:39 PM CDT | Mesoscale Discussion | SPC | Brown, Cass, Champaign, Christian, Coles, DeWitt and 24 more | 2 hr |
Nearby
Mesoscale Discussions in Illinois, 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.