Severe Thunderstorm Warning 192, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
647 PM CDT Tue Sep 1 2026

.KEY MESSAGES...

- A storm complex moves into the region tonight along and north
  of I-90 (40-70%). Storms could be strong to severe with
  damaging winds the main threat.

- Additional storm chances exist Wednesday afternoon (10-20%)
  and Thursday morning (30-60%).

- Daily shower/storm chances continue through the weekend with
  warm temperatures though these may trend cooler by Sunday.

&&

.DISCUSSION...
Issued at 113 PM CDT Tue Sep 1 2026

Tonight - Wednesday Morning: Strong to Severe Storms Late Tonight

A shortwave trough lifting northward out of Nebraska this
afternoon will spark showers and storms across the northern
Great Plains before growing upscale into an MCS that moves
eastward towards the Upper Mississippi River Valley. MUCAPE and
effective shear are expected to be supportive of strong to
severe convection with this MCS generally 1500-2500 J/kg and
35-45kts, respectively though the majority of the effective
shear occurs within the 0-3km layer. Thinking the MCS will be
strongest across our Minnesota counties though some stronger
updrafts may continue into Wisconsin especially with support
from the nocturnal low level jet. Storms should largely be
elevated given the stable near surface layer, mitigating the
tornado threat, and skinny CAPE profiles should limit hail
growth such that the main threat is damaging winds as DCAPE
values exceed 750 J/kg.

Placement and timing of the MCS is a bit challenging with many
different CAM solutions and quite a bit of run to run
variability. As of right now, arrival of the MCS to the I-35
corridor looks to be between 12-4 am, moving through our area
during the early morning hours. CAMs suggest it moves along and
just north of I-90 where the MUCAPE gradient is maximized. Some
solutions do suggest a further northward placement may occur,
though these are outliers and confidence is highest in the near
I-90 solution, especially with a southward trend noted in the
01.12z HREF as compared to 12-24 hours ago.

Another aspect to watch is rainfall amounts due to PWATs of
1.5-1.6 inches, above the 90th percentile of climatology, and
the skinny CAPE profiles. Probabilities for rainfall amounts
exceeding 1 inch are 20-40% in the 01.12z HREF though locally
higher amounts of 2+ inches are possible per the 01.12z HREF
LPMM. Fortunately the system will be progressive and areas along
and north of I-90 have also been fairly dry meaning the soil
will be able to handle even the higher end rainfall amounts.

Wednesday Afternoon - Thursday Morning: Afternoon and Overnight
Storms

After the morning's MCS, another warm and humid day is in store
for Wednesday while a quasi-stationary frontal boundary remains
situated across our southern counties through the afternoon.
Given the warm and humid conditions, instability, albeit capped,
builds across the region in the vicinity of the boundary with
MUCAPE values of 2000-3000 J/kg. While forcing is weak,
somewhat nebulous, and the low levels remain capped some
convective development appears possible during the afternoon
given warm air advection and moisture transport into the
boundary. This potential is low however, generally 10-20%.
AI/ML guidance does suggest some potential for a stronger storm
exists due to the instability present though this is a very low
chance (<5%) with the more favorable environment existing to
our east.

Another MCS is possible Wednesday night into Thursday morning
as the 850hPa nocturnal low level jet intensifies again. Can't
rule out some stronger storms, mainly north of I-90 as the
surface boundary begins to lift northward, with MUCAPE values of
1500-2500 J/kg remaining across the region although shear is
less favorable for strong to severe convection as an upper level
jet streak propagates eastward. Could see another round of
rainfall to around 1/2 inch with probabilities for greater than
1/2 inch in the 01.00z LREF around 20-30%.

Thursday Afternoon - Sunday: Daily Storm Chances and Warm

Additional shortwaves traverse the northern extent of a
building upper ridge through the remainder of the week into this
weekend. Daily chances for showers and storms exist with these
waves, ranging from 20-60% in the 01.13z NBM, but overall
details are not clear. Warm temperatures also continue through
Saturday with the NBM mean suggesting highs should be in the
mid to upper 80s though current trends suggest a bit of a cool
down is in store for Sunday with highs in the upper 70s to low
80s.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 647 PM CDT Tue Sep 1 2026

Scattered showers and some storms are ongoing along the I-90
corridor. Expect this to continue over the next couple of hours
at least. A thunderstorm complex or two will move through the
region during the overnight with damaging winds being the main
threat. CIGS should stay above MVFR but there remains a chance
(40%) that MVFR or lower CIGS could occur. During bouts of
heavier rainfall, lowered visibilities will drop flight
categories. All rain chances are expected to end by mid morning
Wednesday. Winds stay variable until Wednesday afternoon when
most locations see southwest winds.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

DISCUSSION...Falkinham
AVIATION...Cecava

Hazardous Weather Outlook
National Weather Service La Crosse WI
139 PM CDT Tue Sep 1 2026

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-022245-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
139 PM CDT Tue Sep 1 2026

This Hazardous Weather Outlook is for portions of southeast
Minnesota...northeast Iowa and southwest into central Wisconsin.

.DAY ONE...This Afternoon and Tonight

A strong to severe thunderstorm complex moves through the area
late tonight into Wednesday morning, mainly along and north of
Interstate 90. The primary hazard is damaging winds.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Strong thunderstorms are possible Wednesday night through
Thursday morning. The primary hazard is damaging winds.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Special Weather Statement
National Weather Service La Crosse WI
1019 PM CDT Tue Sep 1 2026

MNZ088-095-020400-
Fillmore MN-Winona MN-
1019 PM CDT Tue Sep 1 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN WINONA AND
NORTHEASTERN FILLMORE COUNTIES THROUGH 1100 PM CDT...

At 1019 PM CDT, Doppler radar was tracking a strong thunderstorm near
Fountain, or near Preston, moving northeast at 25 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This storm will remain over mainly rural areas of southwestern Winona
and northeastern Fillmore Counties, including the following
locations... Saratoga, Arendahl, County Roads 6 And 33, Whalan, Pilot
Mound, Old Barn Campground, Isinours, Peterson, Fremont, and Troy.

This includes Interstate 90 in Minnesota between mile markers 234 and
239.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4385 9210 4385 9208 4389 9208 4397 9204
      4386 9173 4364 9197 4372 9217
TIME...MOT...LOC 0319Z 212DEG 20KT 4376 9206

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Naylor

Special Weather Statement
National Weather Service La Crosse WI
1045 PM CDT Tue Sep 1 2026

MNZ088-020430-
Winona MN-
1045 PM CDT Tue Sep 1 2026

...A STRONG THUNDERSTORM WILL IMPACT WESTERN WINONA COUNTY THROUGH
1130 PM CDT...

At 1045 PM CDT, Doppler radar was tracking a strong thunderstorm near
Lewiston, or 11 miles southwest of Winona, moving northeast at 30
mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This strong thunderstorm will be near...
  Winona and Stockton around 1055 PM CDT.
  Goodview around 1100 PM CDT.
  Fountain City around 1105 PM CDT.

Other locations impacted by this storm include Witoka, Wyattville,
Wilson, Hart, Minnesota City, Pickwick, Fremont, and Rushford
Village.

This includes Interstate 90 in Minnesota between mile markers 241 and
258.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4414 9176 4412 9171 4410 9171 4410 9168
      4407 9166 4405 9161 4403 9159 4402 9151
      4401 9149 4384 9168 4385 9198
TIME...MOT...LOC 0345Z 216DEG 26KT 4391 9181

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Naylor

Special Weather Statement
National Weather Service La Crosse WI
1125 PM CDT Tue Sep 1 2026

WIZ034-041-042-020515-
Jackson WI-La Crosse WI-Monroe WI-
1125 PM CDT Tue Sep 1 2026

...STRONG THUNDERSTORMS WILL IMPACT LA CROSSE...SOUTHWESTERN JACKSON
AND NORTHWESTERN MONROE COUNTIES THROUGH 1215 AM CDT...

At 1124 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Holmen to near Bangor. Movement was northeast
at 35 mph.

HAZARD...Wind gusts up to 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Strong thunderstorms will be near...
  Sparta and Holmen around 1130 PM CDT.
  Fort Mc Coy around 1145 PM CDT.
  Cataract around 1150 PM CDT.

Other locations impacted by these storms include Melrose,
Stevenstown, Rockland, County Roads D E And E, Severson Coulee,
Mindoro, Four Corners, Nathan Hill, Veterans Memorial Park, and
Midway.

This includes the following highways...
 Interstate 94 between mile markers 139 and 141.
 Interstate 90 in Wisconsin between mile markers 2 and 33.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4408 9046 4382 9084 4386 9127 4389 9132
      4393 9134 4396 9139 4399 9132 4400 9133
      4406 9125 4405 9122 4409 9120 4409 9117
      4408 9115 4413 9115 4416 9110
TIME...MOT...LOC 0424Z 241DEG 29KT 4396 9128 4389 9089

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Naylor

Special Weather Statement
National Weather Service La Crosse WI
1151 PM CDT Tue Sep 1 2026

MNZ088-WIZ032-020515-
Winona MN-Buffalo WI-
1151 PM CDT Tue Sep 1 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN WINONA AND
SOUTHEASTERN BUFFALO COUNTIES THROUGH 1215 AM CDT...

At 1151 PM CDT, Doppler radar was tracking a strong thunderstorm 7
miles south of Winona, moving east at 20 mph.

HAZARD...Wind gusts up to 40 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This strong thunderstorm will be near...
  Winona around 1155 PM CDT.

Other locations impacted by this storm include Wilson, Witoka,
Marshland, Ridgeway, and Pickwick.

This includes Interstate 90 in Minnesota between mile markers 248 and
266.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4410 9155 4408 9154 4404 9157 4403 9156
      4402 9156 4402 9151 4397 9142 4391 9145
      4390 9178 4398 9178
TIME...MOT...LOC 0451Z 256DEG 19KT 4395 9165

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

Naylor

Preliminary Local Storm Report
National Weather Service La Crosse WI
1228 AM CDT Wed Sep 2 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1210 AM     Hail             6 ENE Pickwick          44.01N 91.49W
09/02/2026  M1.50 Inch       Winona             MN   Fire Dept/Rescue

            Multiple reports of 1 to 1.5 inch hail
            sizes. Time estimated from radar.

&&