Special Weather Statement, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
418 AM CDT Mon Jul 20 2026

.KEY MESSAGES...

- Initial round of storms progressing southeast through
  Minnesota on RADAR imagery mainly a wind/hail threat should
  their strength persist. Overall risk of this being severe is
  low (<10%).

- Subsequent round of storms this afternoon and evening continues
  to have signficiant uncertainty due to dependency on
  departure of ongoing morning storms. If and where storms do
  form, they will have a higher potential of being severe
  (30-40%). All hazards will be possible including damaging
  winds, large hail, a few tornadoes, and heavy rain.

- Cooler temperatures are on the horizon with dry conditions
  expected starting Tuesday.

&&

.DISCUSSION...
Issued at 408 AM CDT Mon Jul 20 2026

This Morning: Round 1 of Storms

A cluster of storms, currently ongoing across south-central
Minnesota this morning, will move southeast through the Coulee
Region as we approach daybreak. Members of the 00Z HREF have
come into much better agreement as to the track of this MCS
compared to earlier 12/18Z runs with it tracking into southeast
Minnesota and generally along the Mississippi River. There is
still some uncertainty as to the strength of this activity by
the time it gets to our neck of the woods. While storm strength
has persisted on RADAR, entirely elevated instability may
continue to limit surface impacts as seen in recent observations.

Additionally, the nocturnal jet is expected to be on a downward
trend as it is moving into our area. There will be some hail
risk with these morning storms given the abundance of elevated
instability (1000-2000 MUCAPE and 50 kts of effective shear).
The main question will be how long these storms linger with some
guidance pushing these storms out quickly and others building
activity in the immediate vicinity behind it. How quickly these
storms vacate the area will play a significant role subsequent
storm development detailed below.

This Afternoon - Tonight: Round 2 of Storms - Strong to Severe Likely

An upper level shortwave trough over the Canadian Plains is expected
to continue east southeast through the overnight hours, dropping
into the Upper Midwest and Great Lakes Region by late morning/early
afternoon. This will send a belt of strong mid and upper level winds
through through region with 50-70 kts at 500 mb and 100+ kts at 300
mb. At the surface, a cold front is expected to push into SE
Minnesota and Western Wisconsin, likely by mid-afternoon; with
a warm front potentially in the vicinity of the Mississippi River.

Significant questions remain as to how the morning storms will
impact the airmass for the afternoon storms. The potential
parameter space is severe-supportive with 50-60 kts of shear
and 3000-4000+ J/kg SBCAPE; should morning storms clear out
fairly quickly, giving the airmass time to recover. It's
possible that the southwesterly winds that are expected to
materialize by late morning could help destabilize us regardless
of lingering morning convection. Overall, the longer the
convection lingers into the morning hours, the more complicated
the forecast gets for the afternoon, regarding both timing and
location.

Where storms can and do develop, an all hazards
severe threat looks likely. As mentioned before, shear will be
plentiful upwards of 60 (maybe even 70) kts with fairly
significant veering in the lower levels and effective SRH values
around 300 m2/s2 along and ahead of the front. Any storm
development will have the potential to produce strong downburst
winds with DCAPE values projected to be well over 1000 J/kg per
19.00 HRRR soundings. Cooling aloft will allow for lapse rates
to exceed 7 deg C/km, increasing the significant hail threat.
Dew points in the 70s and deep moisture through the profile will
allow for pWats to climb into the 1.75-2+ inch range tomorrow,
creating a brief heavy rain threat. Flooding does not look to be
of concern as storms should be progressive enough to limit
flooding problems but these will be efficient rain producers so
quick bouts of heavy rain will certainly be possible. Initial
storms along the front are expected to be supercells with the
threat transitioning more to wind/hail as storms grow upscale
into more bowing structures as they move to the east/southeast.

Tuesday - Beyond: Cooler Temperatures and Generally Dry

Once the cold front passes and the storms clear out late Monday
night, there should be a noticeable difference across the area with
an overall much cooler airmass expected for mid week. Temperatures
Tuesday and Wednesday will finally drop below average into the
upper 70s to low 80s with dry conditions expected as a weak
surface high pressure moves in behind the front. While a quick
moving disturbance may bring some low rain chances to the area
by late week, expect generally dry conditions and near normal
temperatures to round out the next work week.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1241 AM CDT Mon Jul 20 2026

Ongoing smoke impacts expected to lift east through the early
morning hours as TSRA chances increase from northwest to
southeast through the morning hours. Radar imagery at 06Z TAF
issuance exhibits local morning storms crossing the South Dakota
border into Minnesota. Strong to severe storms are possible
depending on exact timing of storms.

Eastern extent of morning storms will determine subsequent storm
chances at local TAF sites (KLSE/KRST). Higher threat and
confidence in local storms at KLSE (over KRST) given the more
eastern longitude and potential daytime recovery of low level
instability.

&&

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

&&

DISCUSSION...Barendse
AVIATION...JAR

Hazardous Weather Outlook
National Weather Service La Crosse WI
430 AM CDT Mon Jul 20 2026

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-211000-
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-
430 AM CDT Mon Jul 20 2026

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

.DAY ONE...Today and Tonight

Air Quality Alerts remain in effect through the morning hours for
unhealthy air quality due to wildfire smoke.

Strong to severe storms are possible through the afternoon into
tonight with damaging winds, large hail, and a few tornadoes
possible.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Severe reports are appreciated.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Special Weather Statement
National Weather Service La Crosse WI
449 AM CDT Mon Jul 20 2026

MNZ079-086>088-094-095-WIZ032-033-201045-
Wabasha MN-Olmsted MN-Dodge MN-Fillmore MN-Winona MN-Mower MN-
Buffalo WI-Trempealeau WI-
449 AM CDT Mon Jul 20 2026

...STRONG THUNDERSTORMS WILL IMPACT WINONA...OLMSTED...MOWER...
WABASHA...DODGE...FILLMORE...BUFFALO AND NORTHWESTERN TREMPEALEAU
COUNTIES THROUGH 545 AM CDT...

At 448 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Plum City to near Mantorville to near
Clarks Grove. Movement was southeast at 40 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Strong thunderstorms will be near...
  Rochester, Mantorville, Kasson, Byron, Hayfield, and Oronoco
  around 455 AM CDT.
  Austin around 500 AM CDT.
  Wabasha and Brownsdale around 505 AM CDT.
  Plainview and Elgin around 510 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4397 9305 4420 9273 4419 9255 4436 9255
      4437 9243 4445 9243 4445 9224 4441 9208
      4460 9200 4459 9117 4447 9117 4365 9191
      4350 9215 4350 9305
TIME...MOT...LOC 0948Z 304DEG 37KT 4463 9225 4409 9278 4373 9334

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

JSB

Special Weather Statement
National Weather Service La Crosse WI
554 AM CDT Mon Jul 20 2026

IAZ008>010-018-019-MNZ094>096-201200-
Floyd IA-Winneshiek IA-Chickasaw IA-Howard IA-Mitchell IA-
Fillmore MN-Mower MN-Houston MN-
554 AM CDT Mon Jul 20 2026

...STRONG THUNDERSTORMS WILL IMPACT MITCHELL...HOWARD...FLOYD...
WINNESHIEK...CHICKASAW...SOUTHEASTERN MOWER...SOUTHWESTERN HOUSTON
AND FILLMORE COUNTIES THROUGH 700 AM CDT...

At 553 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Fountain to 7 miles southwest of St.
Ansgar. Movement was south at 40 mph.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Strong thunderstorms will be near...
  Harmony, Lime Springs, and Rudd around 605 AM CDT.
  Floyd around 610 AM CDT.
  Cresco and Elma around 615 AM CDT.
  Charles City around 620 AM CDT.
  Ridgeway, Ionia, and Jerico around 630 AM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4332 9302 4378 9211 4348 9161 4311 9161
      4308 9167 4308 9208 4291 9208 4291 9269
      4319 9303
TIME...MOT...LOC 1053Z 337DEG 34KT 4371 9215 4328 9300

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

JSB