Alert archive / Minnesota / Mesoscale Discussions in 2025

Mesoscale Discussion 1908

August 9, 202516 counties in Iowa; 44 counties in Minnesota; 9 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2025, 2:40 AM CDT for 16 counties in Iowa; 44 counties in Minnesota; 9 counties in Wisconsin. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Aug 9, 2025, 2:40 AM CDT (07:40 UTC)
Expired
Aug 9, 2025, 4:15 AM CDT
In force
95 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 578
All 69 counties

Buena Vista County, IA, Cerro Gordo County, IA, Cherokee County, IA, Clay County, IA, Dickinson County, IA, Emmet County, IA, Hancock County, IA, Humboldt County, IA, Kossuth County, IA, O'Brien County, IA, Osceola County, IA, Palo Alto County, IA, Pocahontas County, IA, Winnebago County, IA, Worth County, IA, Wright County, IA, Aitkin County, MN, Anoka County, MN, Benton County, MN, Blue Earth County, MN, Brown County, MN, Carlton County, MN, Carver County, MN, Chisago County, MN, Cook County, MN, Cottonwood County, MN, Crow Wing County, MN, Dakota County, MN, Dodge County, MN, Faribault County, MN, Freeborn County, MN, Goodhue County, MN, Hennepin County, MN, Isanti County, MN, Itasca County, MN, Jackson County, MN, Kanabec County, MN, Lake County, MN, Le Sueur County, MN, Martin County, MN, McLeod County, MN, Meeker County, MN, Mille Lacs County, MN, Morrison County, MN, Mower County, MN, Nicollet County, MN, Pine County, MN, Ramsey County, MN, Renville County, MN, Rice County, MN, Saint Louis County, MN, Scott County, MN, Sherburne County, MN, Sibley County, MN, Stearns County, MN, Steele County, MN, Waseca County, MN, Washington County, MN, Watonwan County, MN, Wright County, MN, Barron County, WI, Bayfield County, WI, Burnett County, WI, Douglas County, WI, Dunn County, WI, Pierce County, WI, Polk County, WI, Saint Croix County, WI, Washburn County, WI

The radar

The Minneapolis radar (KMPX), 22 km from the middle of the area, began a volume at 07:40 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

Minneapolis, MN (KMPX), launched 00:00Z, 7.7 hours before the alert went out and 24 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.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2025-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4021 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2025-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 92 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
4021 J/kg
Mixed-layer CIN
-141 J/kg
Mixed-layer LCL
911 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
92 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

118 
ACUS11 KWNS 090740
SWOMCD
SPC MCD 090740 
MNZ000-WIZ000-IAZ000-090915-

Mesoscale Discussion 1908
NWS Storm Prediction Center Norman OK
0240 AM CDT Sat Aug 09 2025

Areas affected...portions of MN into northwest WI and IA

Concerning...Severe Thunderstorm Watch 578...

Valid 090740Z - 090915Z

The severe weather threat for Severe Thunderstorm Watch 578
continues.

SUMMARY...Isolated to widely scattered storms may produce strong to
severe wind gusts into early morning across eastern portions of
Minnesota, northwest Wisconsin, and portions of northern Iowa.

DISCUSSION...Storms have modestly increased in coverage/intensity
over the past 1-2 hours ahead of the east/southeast-advancing cold
front. A very moist airmass beneath steep midlevel lapse rates is
supporting a corridor of strong instability greater than 2500 J/kg.
Stronger vertical shear lags somewhat behind the front across IA
into southeast MN/northwest WI, but a 30-40 kt low-level jet is
evident across the region. Convection has been somewhat slow to
increase/organize, but will likely persist in the favorable
thermodynamic environment as large-scale ascent continues to slowly
overspread the Mid-MO/Upper MS Valleys into early morning. Damaging
wind gusts will be the main hazard with this activity, though
isolated large hail is possible with any more discrete cellular
activity. 

Severe Thunderstorm Watch 578 is set to expire at 09z. Given
convection is likely to persist, a local watch extension or a new
watch issuance is possible for parts of the MCD area.

..Leitman.. 08/09/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...DLH...ARX...MPX...DMX...FSD...

LAT...LON   42509608 48589323 48238987 45549139 42559354 42509608 

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 8, 9:34 PM CDTSevere Thunderstorm WatchSPCBuena Vista, Cherokee, Clay, Dickinson, Ida, Lyon and 3 more8 hr
Aug 8, 11:25 PM CDTMesoscale DiscussionSPCDickinson, Emmet, Lyon, Osceola2 hr
Aug 9, 2:17 AM CDTSevere Thunderstorm WatchSPCHarrison, Mills, Monona, Pottawattamie, Shelby5 hr
Aug 9, 5:31 AM CDTMesoscale DiscussionSPCAdair, Audubon, Boone, Calhoun, Carroll, Cass and 21 more89 min
Aug 9, 6:04 AM CDTSevere Thunderstorm WatchSPCAdair, Audubon, Boone, Calhoun, Carroll, Cass and 23 more5 hr
Aug 9, 7:29 AM CDTMesoscale DiscussionSPCAdair, Audubon, Boone, Bremer, Butler, Calhoun and 30 more2 hr
Aug 9, 10:03 AM CDTMesoscale DiscussionSPCAllamakee, Chickasaw, Clayton, Fayette, Howard, Winneshiek87 min
Aug 9, 2:54 PM CDTMesoscale DiscussionSPCCedar, Clinton, Davis, Des Moines, Henry, Jefferson and 5 more96 min
Aug 8, 8:39 PM CDTMesoscale DiscussionSPCAitkin, Anoka, Benton, Brown, Carlton, Carver and 44 more2 hr

Nearby

Mesoscale Discussions in Minnesota, 2025Mesoscale Discussions in Iowa, 2025Mesoscale Discussions in Wisconsin, 2025Every mesoscale discussion in 2025

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.