229
FXUS63 KARX 281735
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1235 PM CDT Fri Aug 28 2026

.KEY MESSAGES...

- Rain shower and thunderstorm chances increase on Saturday with another
  round on Sunday and some of the storms on Sunday could be
  strong to severe.

- Daily chances for rain continue each day next week with
  temperatures near to slightly above average.

&&

.DISCUSSION...
Issued at 1230 PM CDT Fri Aug 28 2026

This Afternoon Through Sunday: Showers and Thunderstorms Return

Another beautiful weather day will occur this afternoon across the
Driftless region! Very similar to the last few days, a light breeze
will be in the air and temperatures will rise into the upper 70s to
low 80s for highs this afternoon. Today would be a great day to get
outdoors and enjoy the nice weather before the potential for rain
returns as well as warmer temperatures.

Speaking of the rain potential, northerly flow aloft today begins to
become more northwest to west this evening into Saturday morning.
This change in the upper level flow opens the door to shortwave
troughs to ride the top of the ridge through the weekend. Strong mid
level theta-e advection will occur out ahead of the first
disturbance that is progged to move over the Upper Midwest beginning
Saturday morning. Widespread showers should form as a result and the
system should move from west to east during Saturday morning into
the afternoon. There may be just enough instability present for a
few storms to form, but they will be few and far between. The 28/12z
HREF mean PWAT values are near the climatological max based on
sounding data from KMPX, so the rain showers may be efficient rain
producers, especially with any stronger cores/storms that may form.
Even though there could be heavy rain at times, flooding is not
expected as the system will be fairly quick moving.

The potential for rainfall on Sunday is more uncertain as there are
timing and mesoscale differences in the forecast guidance. Right now
there are off and on chances throughout the day given the
uncertainty. Some forecast models do depict the potential for some
storms to become strong to severe on Sunday afternoon into the
evening, but confidence in that scenario panning out are very,
very low right now. A majority of guidance depicts strong WAA at
H850 which would lead to strong capping, but there are a few
models hinting that the WAA may be overdone. If the severe storm
threat were to pan out, damaging wind gusts and large hail
would be the primary hazards. Temperatures on Sunday could be
quite warm in response to the increased low level temperatures
with forecast highs in the mid to upper 80s.

Next Week: Daily Rain Chances with Warm Conditions

There is fairly good consistency to the expected upper level pattern
for next week, with the center of high pressure sitting over the
southeast and troughing across the northwestern CONUS. The northern
extent of the ridge is the main area of uncertainty right now and
will play a large factor in the weather for next week. The GFS/GEFS
are currently an outlier in the ensemble model suite and they are
indicating near record breaking heat for a few days next week with
highs in the 90s each afternoon. These temperatures appear to be
well overdone as EC/Canadian ensembles are cooler and the AIGFS/AI
Euro are also leaning that way. In fact, the GEFS mean for high
temperatures in the middle to later half of next week is 5 degrees
or higher for temperatures compared to the EC/Canadian ensemble
means. So all that is to say that the NBM blended temperatures,
which are currently in the forecast, may be skewed slightly on the
warmer side due to the apparent warm bias from the GEFS. There is
fairly good agreement that Monday will be a warm day, with highs in
the mid to upper 80s. Beyond Monday is where the guidance really
begins to diverge.

With the flow over the Upper Midwest becoming westerly through the
next work week, this should continue the potential for nearly daily
chances for showers and thunderstorms. There is some concern that
there may be chances for heavy rain in the middle of next week that
could lead to some flooding concerns, but due to the variance in the
upper pattern, confidence in location, timing, etc. is low at this
time.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1230 PM CDT Fri Aug 28 2026

VFR conditions are forecast during the first half of this TAF
cycle. The wind will be light with increasing cloud cover,
especially after sunrise this evening. Rain showers are likely
at all terminals beginning before sunrise on Saturday. Cannot
completely rule out thunderstorms with the showers, but
confidence in thunderstorm impacts are too low to mention. The
light rain may lead to MVFR visibility at times, but have kept
VFR visibility for now. Rain will end from west to east and
should end at KRST near the very end of this 24 hour period.
The wind will increase out of the south at 10-15 kts towards the
end of this TAF cycle.

&&

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

&&

$$

DISCUSSION...Muscha
AVIATION...Muscha