035
FXUS63 KARX 121048
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
548 AM CDT Sat Sep 12 2026

.KEY MESSAGES...

- Widespread rain is likely Monday into Tuesday (70 to 90%) with the
  potential for localized flooding.

- Cooler, more Fall-like, temperatures are forecast over the
  next week for the Upper Midwest.

&&

.DISCUSSION...
Issued at 1247 AM CDT Sat Sep 12 2026

Tonight through Sunday: Rain Chances and Trending Cooler

A line of showers and thunderstorms has formed and is
continuing to move east across southeast Minnesota and western
Wisconsin. The storms should encounter a more stable
environment as they move further east so the severe storm threat
is very, very low for early this morning. The line of showers
with isolated storms may grow further south and quickly move
across the area early this morning before dissipating or moving
off to the east near sunrise.

Quiet weather is forecast for today as the next weather systems
that will impact the reason begin to move in over the Pacific
Northwest and another one attempts to dig south across the Great
Lakes region. One more day of near average high temperatures is
forecast for today, even with a weak frontal passage early
Saturday morning behind the line of showers/storms. Cooler air
will filter in on Sunday as the base of a H500 trough digs south
towards the Upper Midwest and highs should be around 10 degrees
cooler than today`s highs. Quick moving showers aided by weak
synoptic scale support may move over portions of the forecast
area on Sunday. Any rain that does fall should be fairly light
with rain totals of a quarter inch or less.

Monday and Tuesday: Widespread Rain with the Potential for Flooding

The aforementioned low pressure system across the Pacific Northwest
will eject east to northeastward over the Northern Rockies towards
Saskatchewan and Ontario late this weekend into early next week.
This feature will propel a surface cold front over the Northern
Plains towards the Great Lakes during this time frame. Strong H700
theta-e advection is depicted by forecast models out ahead of this
system which should result in rain showers and thunderstorm
development on Monday into Tuesday. Favorable atmospheric profiles
along with high PWAT values approaching 2 inches, as shown by
blended ensemble guidance, should lead to moderate to, at times,
heavy rainfall. Just where and when the heaviest rainfall may fall
continues to vary and will be dependent upon mesoscale factors that
will likely continue to change over the next few days. Mean ensemble
output along with AI based models are trending towards the heaviest
rainfall falling south of the area, but there could be a corridor of
slightly higher totals (2-3 inches) across portions of the CWA. If
heavier rainfall occurs over the area with the few rounds of rain
that are possible, localized flooding concerns may occur.

A secondary, more uncertain, threat may arise on Monday with a
potential for severe thunderstorms. This threat will be highly
conditional and is dependent upon instability being able to build in
throughout the day. Wind shear will not be a problem as low level
wind shear values are upwards of 40-50 kts. Trends regarding the
severe storm threat for Monday will need to be closely monitored
throughout the weekend.

Rest of Next Week: Rain Chances Continue with Cooler Temperatures

The weather pattern over the region will be highly dependent on the
evolution of an upper level trough digging south across the Pacific
Northwest in the middle of next week. Additional rounds of showers
or storms will be possible in the middle of the week as long as mid
level moisture is in place and the trough digs far enough south.
Further pushes of cooler air should continue to move over the region
in this pattern which should keep daily temperatures on the cooler
side for the entire work week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 548 AM CDT Sat Sep 12 2026

MVFR CIGS are beginning to move across southeast Minnesota and
west central Wisconsin and will continue to move southeastward
across the region through the morning. These lowered CIGS will
only stick around a couple of hours then some mid-level clouds
(around 10kft) move in for the remainder of the TAF period.
These MVFR conditions are accompanying a front where winds ahead
of it are out of the southwest and behind it are out of the
northwest. Sustained winds of 10 to 20 mph with gusts up to 25
mph will be possible this morning but then expect sustained
winds of 5 to 15 mph for the afternoon and evening.

&&

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

&&

$$

DISCUSSION...Muscha
AVIATION...Cecava