Alert archive / Wisconsin / Mesoscale Discussions in 2021
Mesoscale Discussion 1382
The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2021, 11:24 PM CDT for Allamakee County, Iowa; Houston County, Wabasha County, Winona County, Minnesota; 40 counties in Wisconsin. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Jul 28, 2021, 11:24 PM CDT (04:24 UTC)
- Expired
- Jul 29, 2021, 1:00 AM CDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 399
All 44 counties
Allamakee County, IA, Houston County, MN, Wabasha County, MN, Winona County, MN, Adams County, WI, Buffalo County, WI, Calumet County, WI, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Fond du Lac County, WI, Grant County, WI, Green County, WI, Green Lake County, WI, Iowa County, WI, Jackson County, WI, Jefferson County, WI, Juneau County, WI, Kenosha County, WI, La Crosse County, WI, Lafayette County, WI, Marquette County, WI, Milwaukee County, WI, Monroe County, WI, Outagamie County, WI, Ozaukee County, WI, Pepin County, WI, Pierce County, WI, Portage County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Trempealeau County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI
The radar
The La Crosse radar (KARX), 107 km from the middle of the area, began a volume at 04:24 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
Green Bay/Straub, WI (KGRB), launched 00:00Z, 4.4 hours before the alert went out and 162 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
- 593 J/kg
- Mixed-layer CIN
- -264 J/kg
- Mixed-layer LCL
- 1088 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 62 m²/s²
- 0-3 km storm-relative helicity
- 154 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
293
ACUS11 KWNS 290425
SWOMCD
SPC MCD 290424
WIZ000-IAZ000-MNZ000-290600-
Mesoscale Discussion 1382
NWS Storm Prediction Center Norman OK
1124 PM CDT Wed Jul 28 2021
Areas affected...East-central MN...WI
Concerning...Severe Thunderstorm Watch 399...
Valid 290424Z - 290600Z
The severe weather threat for Severe Thunderstorm Watch 399
continues.
SUMMARY...The severe threat continues across the watch area, and the
risk for damaging winds, with gusts in excess of 75 mph, will remain
possible. Large hail and a couple tornadoes may also occur.
DISCUSSION...Severe storms producing damaging/significant severe
winds and large hail were in progress across west-central through
central WI as of 0415z. Radar reflectivity and velocity data have
sampled well-organized rear-inflow jets with smaller-scale bowing
segments within the line, with several reports of severe winds
received thus far. Strengthening warm advection in association with
a 40 kt southwesterly low-level jet, and moderate/strong MLCAPE over
much of discussion area, will continue to result in a favorable
downstream environment into the overnight time frame. Current
expectations are for storms to continue moving south/southeast along
an instability gradient over far southeast MN, southern WI and
perhaps extreme northeast IA through 07z.
..Bunting.. 07/29/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GRB...MKX...ARX...MPX...
LAT...LON 44759241 44669013 44468868 44318776 43768729 43078731
42598756 42558885 42548985 42909097 43899223 44669271
44759241SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 7:17 PM CDT | Severe Thunderstorm Watch | SPC | Allamakee, Clayton, Fayette, Winneshiek | 7 hr |
| Jul 29, 2:19 PM CDT | Mesoscale Discussion | SPC | Davis, Lee, Van Buren | 116 min |
| Jul 28, 10:17 PM CDT | Mesoscale Discussion | SPC | Goodhue, Olmsted, Wabasha, Washington, Winona | 58 min |
| Jul 28, 8:59 PM CDT | Mesoscale Discussion | SPC | Chippewa, Clark, Eau Claire, Jackson, Monroe, Trempealeau | 61 min |
| Jul 28, 9:51 PM CDT | Mesoscale Discussion | SPC | Eau Claire, Jackson, Monroe | 54 min |
| Jul 29, 1:34 AM CDT | Mesoscale Discussion | SPC | Kenosha, Milwaukee, Racine, Rock, Walworth, Waukesha | 86 min |
Nearby
Mesoscale Discussions in Wisconsin, 2021Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Iowa, 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.