Alert archive / Wisconsin / Mesoscale Discussions in 2021
Mesoscale Discussion 1287
The Storm Prediction Center issued this mesoscale discussion at Jul 14, 2021, 5:42 PM CDT for 4 counties in Illinois; 6 counties in Iowa; 11 counties in Wisconsin. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Jul 14, 2021, 5:42 PM CDT (22:42 UTC)
- Expired
- Jul 14, 2021, 6:45 PM CDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 21 counties
Allamakee County, IA, Clayton County, IA, Delaware County, IA, Dubuque County, IA, Jackson County, IA, Jones County, IA, Carroll County, IL, Jo Daviess County, IL, Stephenson County, IL, Winnebago County, IL, Columbia County, WI, Crawford County, WI, Dane County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Richland County, WI, Rock County, WI, Sauk County, WI
The radar
The La Crosse radar (KARX), 133 km from the middle of the area, began a volume at 22:42 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 10.7 hours before the alert went out and 136 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.
784 ACUS11 KWNS 142242 SWOMCD SPC MCD 142242 WIZ000-ILZ000-IAZ000-142345- Mesoscale Discussion 1287 NWS Storm Prediction Center Norman OK 0542 PM CDT Wed Jul 14 2021 Areas affected...Eastern IA...Northern IL...Southern WI Concerning...Severe potential...Watch likely Valid 142242Z - 142345Z Probability of Watch Issuance...80 percent SUMMARY...Severe threat is increasing across eastern IA/northwestern IL into southern WI. New ww will likely be warranted soon. DISCUSSION...Early-day MCS has progressed across the upper Midwest with the leading edge now spreading across LE. Considerable boundary-layer disruption has been noted across WI/northern IL into extreme northeast IA. However, over the last few hours, partial clearing across eastern IA has allowed surface temperatures to warm into the lower 80s from east of ALO-MXO-CWI-north of C75 in Illinois. Further recover appears likely to near the WI/IL border over the next few hours. While updrafts may struggle to be truly surface-based where temperatures struggle to rise above 75F, there is increasing concern/confidence that ongoing supercells over central IA will progress east of ww378 into a region that is recovering in the wake of earlier convection. Ample shear/buoyancy suggest supercells will continue, along with a tornado threat. Additionally, LLJ is forecast to increase across southern/central WI this evening and this should encourage renewed convective development. New ww will likely be issued soon. ..Darrow/Guyer.. 07/14/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX... LAT...LON 43269164 43638913 42848852 42168919 41829151 43269164
SPC 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, 2:01 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 9 more | 119 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 | Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 13 more | 5 hr |
| Jul 14, 1:40 PM CDT | Mesoscale Discussion | SPC | Audubon, Black Hawk, Boone, Bremer, Buena Vista, Butler and 38 more | 2 hr |
| Jul 14, 2:35 PM CDT | Tornado Watch | SPC | Audubon, Benton, Black Hawk, Boone, Bremer, Buchanan and 41 more | 8 hr |
| Jul 14, 4:17 PM CDT | Mesoscale Discussion | SPC | Boone, Butler, Calhoun, Franklin, Greene, Grundy and 5 more | 58 min |
| Jul 14, 5:47 PM CDT | Mesoscale Discussion | SPC | Audubon, Benton, Black Hawk, Boone, Bremer, Buchanan and 29 more | 118 min |
Nearby
Mesoscale Discussions in Wisconsin, 2021Mesoscale Discussions in Iowa, 2021Mesoscale 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.