400
FXUS63 KARX 270008
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
708 PM CDT Sat Sep 26 2026

.KEY MESSAGES...

- Light rain chances continue through Sunday morning with the highest
  chances (40-70%) west of the Mississippi River through
  sunrise on Sunday.

- After a dry Sunday night through Monday, rain chances return on
  Tuesday through the rest of the week.

- Temperatures will remain seasonal in the 60s to 70s.

&&

.DISCUSSION...
Issued at 120 PM CDT Sat Sep 26 2026

This afternoon through Sunday: Scattered Light Rain Showers

An H500 shortwave trough is moving over the region today and is
aiding in developing light rain showers across Iowa and Minnesota.
Most of the activity today should stay to the west of the
Mississippi River, where the higher moisture and stronger forcing
are located. Any rain amounts for today should be very light, the
HREF has around a 20-50% chance for rainfall to exceed a quarter
inch near I-35 and into the far western portions of the CWA by
Sunday morning. Scattered showers may develop further east overnight
into Wisconsin, but amounts should remain light as the moisture axis
shifts slowly to the east. Rain showers should decrease in coverage
by late Sunday morning as synoptic scale lift decreases over the
Upper Midwest. Temperatures both today and Sunday should mainly be
in the 60s, with some locations reaching the lower 70s.

Monday and Tuesday: Dry Monday - Rain Chances Return Tuesday

The forecast area will be in between two different weather systems
to start the next work week. A low pressure system will continue to
remain over the northeastern US and a trough will dig south across
the western CONUS. Pleasant conditions overall are expected on
Monday with temperatures in the lower 70s and partly cloudy skies
with very little wind. As the aforementioned trough continues to dig
south over the Desert Southwest on Tuesday, moisture should surge
northward out ahead of this feature. Sufficient PVA supplied by
shortwaves embedded in the upper level flow should lead to rain
showers and potentially thunderstorms developing across the region
on Tuesday into Wednesday morning. Just how much rain we receive
from the initial bands of showers and storms will be dependent upon
the moisture quality going into Wednesday morning. The 90th
percentile rainfall amounts from the LREF do indicate the potential
for some locations to see an inch of rainfall or more, but
confidence is low at this time.

Rest of Next Week: Daily Rain Chances May Continue

The remainder of this forecast period is highly uncertain as it will
depend upon the evolution of the low pressure center associated with
the synoptic scale trough as well as how this feature combines with
the remnants of now Hurricane Polo. Ensemble guidance along with
deterministic forecast models indicate plenty of differences in
timing and location in the axis of better rain chances for Wednesday
and beyond. This is shown really well in the NBM PoP values, which
keep at least low to medium (20-50%) chances for rain through
Friday. The current expectation is that the heaviest rainfall will
stay south of the Upper Midwest, but there are outlier solutions
that produce 2+ inches of rainfall during the later half of this
upcoming week. Temperatures are forecast to remain near average to
end the month of September.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 706 PM CDT Sat Sep 26 2026

VFR conditions currently present across the region with light winds
out of the southeast. Some light rain showers will continue across
portions of SE Minnesota and NE Iowa this evening with additional
development expected again overnight. This activity should be
scattered in nature so have continued with/added some PROB30s
as confidence in location remains too low to go prevailing at
this time. Impacts would mainly be focused on the KRST terminal
and areas west of the Mississippi River. MVFR CIGs are expected
to build into the KRST terminal overnight and likely continue
for much of the period tomorrow, potentially scattering out by
mid to late afternoon. Otherwise, VFR conditions and light winds
will prevail for KLSE and areas eastward.

&&

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

&&

$$

DISCUSSION...Muscha
AVIATION...Barendse