Alert archive / Illinois / Mesoscale Discussions in 2021
Mesoscale Discussion 1282
The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2021, 2:01 PM CDT for 15 counties in Illinois; 12 counties in Wisconsin. It was in force for 119 min.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2021, 2:01 PM CDT (19:01 UTC)
- Expired
- Jul 14, 2021, 4:00 PM CDT
- In force
- 119 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 27 counties
Boone County, IL, Bureau County, IL, Carroll County, IL, Cook County, IL, DeKalb County, IL, DuPage County, IL, Kane County, IL, Kendall County, IL, Lake County, IL, Lee County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Whiteside County, IL, Winnebago County, IL, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Jefferson County, WI, Kenosha County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI
The radar
The Milwaukee radar (KMKX), 73 km from the middle of the area, began a volume at 19:02 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 12:00Z, 7.0 hours before the alert went out and 159 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
- 573 J/kg
- Mixed-layer CIN
- -62 J/kg
- Mixed-layer LCL
- 1106 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 108 m²/s²
- 0-3 km storm-relative helicity
- 139 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.1
The text
As transmitted.
395
ACUS11 KWNS 141901
SWOMCD
SPC MCD 141901
ILZ000-WIZ000-142100-
Mesoscale Discussion 1282
NWS Storm Prediction Center Norman OK
0201 PM CDT Wed Jul 14 2021
Areas affected...southern Wisconsin...far northern Illinois
Concerning...Severe potential...Watch possible
Valid 141901Z - 142100Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated wind damage or marginal hail will be possible
over the next few hours, mainly focused over southern Wisconsin.
DISCUSSION...An extensive line of storms currently stretches from
central into southern WI, and across northwest IL where the line
contains less trailing stratiform precipitation. Indications of
strong to possible severe gusts are currently present with activity
north of the IL border, and these storms may persist as the air mass
remains favorably unstable despite high cloud cover. Around 1000
J/kg MLCAPE exists ahead of these storms, extending south into IL.
Some uptick in storm intensity is possible as the line moves into
slightly more unstable air. Aside from isolated damaging gusts,
marginal hail may occur at times. Convective trends are currently
being monitored for watch potential.
..Jewell/Bunting.. 07/14/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LOT...MKX...DVN...
LAT...LON 41409041 42058994 42588959 42988962 43468921 43798859
43778809 43448776 42918766 42338774 41868749 41618768
41438843 41358926 41298968 41409041SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 14, 7:02 AM CDT | Mesoscale Discussion | SPC | Jo Daviess, Stephenson | 2 hr |
| Jul 14, 11:45 AM CDT | Mesoscale Discussion | SPC | Boone, Carroll, Jo Daviess, McHenry, Ogle, Stephenson and 1 more | 2 hr |
| Jul 14, 5:42 PM CDT | Mesoscale Discussion | SPC | Carroll, Jo Daviess, Stephenson, Winnebago | 63 min |
| Jul 14, 6:13 PM CDT | Tornado Watch | SPC | Carroll, Jo Daviess, Rock Island, Stephenson, Whiteside | 6 hr |
| Jul 14, 8:54 AM CDT | Severe Thunderstorm Watch | SPC | Buffalo, Crawford, Grant, Jackson, La Crosse, Monroe and 3 more | 5 hr |
Nearby
Mesoscale Discussions in Illinois, 2021Mesoscale Discussions in Wisconsin, 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.