809
FXUS63 KARX 221821
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
121 PM CDT Thu Oct 22 2026

.KEY MESSAGES...

- Abnormal warmth continues into this weekend as temperatures
  15-20 degrees above normal are expected.

- Low precipitation potential exists late Saturday into early
  Sunday (10-20%), increasing slightly Monday through Tuesday
  (30-40%).

- Temperatures trend cooler and towards normal through the
  beginning of next week.

&&

.DISCUSSION...
Issued at 120 PM CDT Thu Oct 22 2026

Tonight - Saturday: Abnormal Warmth Continues; Low Precipitation
Potential

Upper level ridging and anomalously high 500hPa heights remain
situated across much of the central United States through at
least Saturday while southerly flow and weak warm air advection
continue under said ridge resulting in 850hPa temperatures
around 10-14C. Given these warm temperatures aloft, continue to
expect abnormal warmth as we head into the weekend, roughly 15
to 20 degrees above normal.

Upper level troughing begins to move across the United
States/Canada border tonight, phasing with a shortwave that
ejects off a cutoff low across the southwest United States.
Surface cyclogenesis occurs over the northern Great Plains on
Friday as a result, leading to a developing 850hPa low level jet
from Nebraska into northern Minnesota Friday afternoon. Given
the proximity of the LLJ to our area along with some weak
700-500hPa PVA associated with the shortwave, can`t rule out a
few light showers/sprinkles for our northern counties Friday
afternoon as suggested by several of the CAMs. However, the vast
majority of the region is expected to remain dry as soundings
depict dry air below 10kft where the strongest forcing will
occur and rather weak forcing within the saturated upper
portions of the atmosphere. Current probabilities for light
showers/sprinkles only sit around 10%.

As the upper level trough and attendant surface low continue
eastward Saturday, the cold front associated with these features
slows down and becomes quasi-stationary across Minnesota into
northern Wisconsin. Moisture pools along the boundary as
southerly flow continues across the region which combined with
forcing along the front and stronger 700-500hPa PVA should lead
to some precipitation development throughout the day Saturday.
However, because the boundary largely remains to our west, most
of the region is again expected to be dry with only those north
and west of an Austin, MN to Wausau, WI line having 10-20%
probabilities to see some light rain.

Sunday - Wednesday: Greater Precipitation Potential, Trending Cooler

The quasi-stationary boundary slowly sags southward throughout
the day Sunday though moisture begins to become more limited
with time and forcing becomes far more nebulous as this feature
becomes separated from its upper level support. While some light
showers are possible Sunday mainly for those north of I-90,
probabilities have come down slightly, sitting around 10-20% in
the 22.13z NBM though as high as 30-40% per the AIFS Ens and
AIGEFS. Regardless, amounts should remain under 0.1".

Greater precipitation potential exists Monday through Tuesday
as the cutoff low across the Desert Southwest begins to lift
northward. How this feature evolves as it moves northward and
where the heaviest rainfall associated with it will occur
remains rather uncertain though. The GEFS/AIGEFS members largely
suggest the low takes a more southern trajectory, keeping
higher probabilities for precipitation across a majority of the
Upper Mississippi River Valley (60-80%) whereas the EPS/AIFS Ens
on the other hand suggest a more northern and western solution,
keeping higher probabilities across Minnesota into northern
Wisconsin. Given the uncertainty, probabilities for
precipitation remain on the lower end, currently sitting around
30-40% in the 22.13z NBM though these probabilities may
increase as the models begin to converge on a solution.

Other than precipitation potential, the passage of the quasi-
stationary front on Sunday will allow cooler temperatures to
begin filtering into the Upper Midwest. There is a great deal of
spread within the 25th-75th and 10th-90th percentiles of the
ensemble guidance related to the temperature forecast Monday
through Wednesday however, around 10 and 20 degrees
respectively, due in no small part to the different scenarios
mentioned above. That said, the overall trend is towards more
seasonable temperatures through the beginning of the new week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1214 PM CDT Thu Oct 22 2026

VFR conditions expected for the next 24 hours at the terminals.
Winds will be light out of the south at less than 10 kts for
much of the period, picking up through the morning hours
tomorrow.

&&

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

&&

$$

DISCUSSION...Falkinham
AVIATION...Barendse

NWS ARX Office Area Forecast Discussion