Severe Thunderstorm Warning 121, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
625 PM CDT Fri Jun 19 2026

.KEY MESSAGES...

- Increasing likelihood (60-80%) for storms this afternoon-
  evening. A few stronger storms possible mainly north of I-90,
  with isolated severe hail/winds (<15% chance).

- Isolated showers may impact Taylor and northern Clark counties
  Saturday afternoon (20% chance).

- Rain potential on Sunday increases heading south from I-90
  (30-60%), highest just south of our forecast area.

&&

.DISCUSSION...
Issued at 1251 PM CDT Fri Jun 19 2026

Scattered storms this afternoon, a few strong to possibly severe

Scattered showers and storms will be the story for this afternoon
and evening ahead of an approaching upper level shortwave advancing
into northern Minnesota. Dewpoints are in the low to mid 50s west of
the Mississippi River and in the mid to upper 40s east, but there
will be a slight uptick in moisture transport from the west this
afternoon ahead of the shortwave. Main question is how much
instability we can build this afternoon with incoming decaying
midday showers and associated clouds. However, there's been a large
portion of central/western Minnesota under few clouds that has seen
strong insolation through the morning, and RAP mesoanalysis suggests
this growing pool of instability will creep eastward through late
afternoon with rather steep low and mid level lapse rates. RAP
suggests potentially 1000-1500 J/kg SBCAPE north of I-90 (likely a
bit high due to over-mixing), though HREF mean SBCAPE is more
on the order of 750-1000 J/kg. Regardless, there will be ample
instability, especially north of I-90. Deep layer bulk shear
profiles will be robust with 0-6km values on the order of 30-60+
knots everywhere except maybe Taylor and northern Clark
counties. Hodographs are somewhat messy but generally straight,
suggesting potential for some splitting storms. Certainly
favorable dynamics for some supercell structures, but forecast
soundings only show deeper CAPE profiles for a brief window of
2-3 hours depending on location so storms will probably be more
low-topped. Hail is likely to be the main hazard and should
mostly be small, but any stronger/deeper/rotating updrafts could
potentially grow isolated severe hail to around quarter size or
slightly larger. DCAPE is marginal at best, so not expecting
much of a severe wind threat but can't rule it out entirely.
Activity will exit our area by late evening.

Isolated showers in north-central Wisconsin Saturday afternoon

In northwest flow on Saturday, steep 0-3km lapse rates will promote
marginal afternoon instability. CAMs have been coming into agreement
on the potential for diurnal showers popping up over northern
Wisconsin heading into the afternoon. So have added small PoPs (20%)
to Taylor into northern Clark counties to account for this, fizzling
out toward sunset.

Sunday rain chances will be highest just to our south

Continuing to monitor Sunday's system and accompanying rain
potential. A developing lee cyclone will rapidly advance from Kansas
into MO/IA/IL with favorable upper dynamics. Strong low level
moisture transport from the Gulf will feed into this system as it
passes by to our south. There is wide north-to-south spread among
ensemble guidance as to this surface low's track, but all
GEFS/GEPS/ENS members keep it south of Wisconsin along with the
heaviest rain. There remains low confidence in whether northeast
Iowa and southwest Wisconsin will be brushed by some of the wrap
around rainfall, if they will miss out entirely, or if the rain
advances even a bit further north. Recent ensemble mean trends all
exhibit slight north-to-south fluctuations that keep the forecast a
bit muddled. So will continue to run with NBM PoPs for now which
still paint a broad brushed 30-40% all the way north to I-90 with
60% in our far south.

Seasonal into next week

Not seeing any big pattern shifts or temperature swings further
out in the extended period. Tuesday looks to bring the next
substantial chance (70%) for rain as an upper wave drops through
in northwest flow aloft.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 623 PM CDT Fri Jun 19 2026

Showers and storms continue moving through the region this
evening as an area of low pressure shifts eastward across
northern Wisconsin. These showers/storms are expected to mainly
impact areas along and north of I-90, bringing MVFR/IFR
visibility and MVFR ceilings, before moving out of the area by
05z. Behind them, VFR conditions are expected, continuing
through the overnight and into Saturday morning for most,
although those north of I-94 have the potential to see MVFR
ceilings develop through mid Saturday morning (40-60% per the
19.18z REFS). Gusty southwest winds continue over the next few
hours, generally 20-30KT, before diminishing to less than 10KT
overnight and veering to the northwest Saturday morning.

&&

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

&&

DISCUSSION...Kurz
AVIATION...Falkinham

Hazardous Weather Outlook
National Weather Service La Crosse WI
101 PM CDT Fri Jun 19 2026

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-201200-
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-
101 PM CDT Fri Jun 19 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 few stronger storms will be possible this afternoon and evening
with isolated large hail and gusty winds.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated this afternoon.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

Kurz

Special Weather Statement
National Weather Service La Crosse WI
333 PM CDT Fri Jun 19 2026

MNZ096-192100-
Houston MN-
333 PM CDT Fri Jun 19 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN HOUSTON COUNTY
THROUGH 400 PM CDT...

At 332 PM CDT, Doppler radar was tracking a strong thunderstorm over
Caledonia, moving east at 40 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.

This strong thunderstorm will be near...
  Brownsville around 350 PM CDT.

Other locations impacted by this storm include Reno, County Roads 3
And 24, Willington Grove, Freeburg, County 5 And Peyton Road,
Wilmington, Lock And Dam 8, County 14 And White Tail Road, Dun Romin
Park Campground, and Eitzen.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4361 9161 4371 9127 4365 9127 4364 9126
      4363 9127 4361 9127 4358 9123 4356 9123
      4354 9125 4352 9122 4350 9122 4350 9161
TIME...MOT...LOC 2032Z 259DEG 34KT 4360 9152

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

Naylor