Alert archive / Wisconsin / Mesoscale Discussions in 2021
Mesoscale Discussion 735
The Storm Prediction Center issued this mesoscale discussion at May 25, 2021, 2:15 PM CDT for Gogebic County, Michigan; 6 counties in Minnesota; 24 counties in Wisconsin. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- May 25, 2021, 2:15 PM CDT (19:15 UTC)
- Expired
- May 25, 2021, 4:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
All 31 counties
Gogebic County, MI, Cook County, MN, Dodge County, MN, Goodhue County, MN, Rice County, MN, Steele County, MN, Wabasha County, MN, Ashland County, WI, Barron County, WI, Bayfield County, WI, Buffalo County, WI, Chippewa County, WI, Clark County, WI, Dunn County, WI, Eau Claire County, WI, Iron County, WI, Jackson County, WI, Lincoln County, WI, Oneida County, WI, Pepin County, WI, Pierce County, WI, Polk County, WI, Price County, WI, Rusk County, WI, Saint Croix County, WI, Sawyer County, WI, Taylor County, WI, Trempealeau County, WI, Vilas County, WI, Washburn County, WI, Wood County, WI
The radar
The Duluth radar (KDLH), 115 km from the middle of the area, began a volume at 19:16 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
Green Bay/Straub, WI (KGRB), launched 12:00Z, 7.3 hours before the alert went out and 300 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
- 96 J/kg
- Mixed-layer CIN
- -140 J/kg
- Mixed-layer LCL
- 1118 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 125 m²/s²
- 0-3 km storm-relative helicity
- 155 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
247
ACUS11 KWNS 251915
SWOMCD
SPC MCD 251915
MIZ000-WIZ000-MNZ000-252115-
Mesoscale Discussion 0735
NWS Storm Prediction Center Norman OK
0215 PM CDT Tue May 25 2021
Areas affected...portions of eastern Minnesota and into northwestern
Wisconsin
Concerning...Severe potential...Watch possible
Valid 251915Z - 252115Z
Probability of Watch Issuance...60 percent
SUMMARY...A gradual increase in storm coverage and associated severe
potential is expected over the next couple of hours. A WW may be
required.
DISCUSSION...Latest surface analysis shows a cold front extending
from western Ontario across eastern Minnesota, which continues to
progress eastward. Ahead of the front, gradual clearing has
resulted heating/destabilization, with 1000 to 1500 J/kg mixed-layer
CAPE now indicated across Wisconsin and southeastern Minnesota.
The 18Z MPX RAOB also reflects the heating/destabilization that is
occurring, with a nearly uncapped boundary layer indicated, and well
over 1000 J/kg mixed-layer CAPE. Correspondingly, bands of TCU/CB
are evolving along and ahead of the front, with a continued/gradual
convective increase expected over the next 1 to 2 hours.
As storms evolve, updraft intensity will likely be aided by
favorably strong speed shear resulting from increasing southwesterly
flow with height through the lower and middle troposphere. As a
result, locally gusty/damaging winds and hail will become
increasingly likely with time, with wind potential greatest where
any linear/banding evolution can occur. While CAM guidance remains
inconsistent with respect to eventual storm coverage, we will
continue to monitor convective evolution, with an eye toward
possible WW issuance this afternoon.
..Goss/Guyer.. 05/25/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MQT...GRB...DLH...ARX...MPX...
LAT...LON 48098965 46478921 44279008 43899341 44079355 45019278
46729159 48099086 48098965SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 25, 2:53 PM CDT | Severe Thunderstorm Watch | SPC | Baraga, Delta, Dickinson, Gogebic, Houghton, Iron and 2 more | 8 hr |
| May 25, 5:17 PM CDT | Mesoscale Discussion | SPC | Gogebic, Iron, Ontonagon | 118 min |
Nearby
Mesoscale Discussions in Wisconsin, 2021Mesoscale Discussions in Minnesota, 2021Mesoscale Discussions in Michigan, 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.