560
FXUS63 KARX 011056
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
556 AM CDT Sat Nov 1 2025

.KEY MESSAGES...

- Cool temperatures continue through the weekend with highs in
  the 40s and low 50s before warming back up into the 50s to
  near 60 degrees for early next week.

- Periodic showers for today and again Sunday night and into
  Monday morning.

&&

.DISCUSSION...
Issued at 322 AM CDT Sat Nov 1 2025

Today - Sunday: Staying Cool with Periodic Shower Chances

A closed upper-level low depicted on GOES-19 water vapor imagery and
01.06z RAP 500mb heights can be noted over the local area early this
morning which has been responsible for much of the shower activity
over the area over the past 12 hours or so. As this system
continues to swing southeast throughout the morning and into the
afternoon, much of the CAMs uniformly agree on diminishing
shower activity across the region by early evening. Overall any
rainfall amounts should be relatively minimal with the 01.00z
HREF having very low probabilities (0-20%) for rainfall amounts
over 0.1" throughout the day. Brief upper-level ridging will
build in behind this system which will in turn help slightly
clear our skies Saturday night and Sunday which combined with
light surface winds tonight may contribute to some patchy fog
formation in light of the recent rainfall.

As a surface low pressure system deepens well to our north in
central Canada, a tightening surface pressure gradient will
develop across the region for Sunday as surface high pressure
pushes southeast associated with the aforementioned ridging.
Consequently, expecting winds to be somewhat breezy for Sunday
with momentum transfer in the RAP/HRRR would suggest some
tendency to mix down 850mb winds of 30-35 kts. As a result,
seeing some potential for wind gusts of 25-35 mph, primarily
west of the Mississippi River. Additionally, with northwesterly
flow still in place aloft, would expect temperatures to remain
fairly steady-state with highs generally in the 40s to lower 50s
through Sunday.

By the time Sunday night rolls around, a shortwave trough with an
attendant surface front will push north of the region extending
some precipitation chances into the local area overnight Sunday
and into Monday morning along this boundary. Overall the grand
ensemble (GEFS/EC/Canadian ensemble) has medium probabilities
(40-70%) for measurable rainfall primarily north of I-90,
particularly in west/north-central Wisconsin. Some differences
remain on exactly how far the western extent for precipitation
is amongst the deterministic models, but the general idea is
higher confidence the further northeast which is reflected in
the NBM precipitation chances (20-50%) with the highest
probabilities in west/north-central Wisconsin. Regardless, the
probability for 0.1" or greater of rainfall in the grand
ensemble is low (10-40%) Sunday night and into Monday morning.

Next Week: Warming Up Slightly, Dry Start to the Week

As we start the new work week, the aforementioned trough pushes east
allowing for northwesterly flow to shift to a more zonal flow regime
aloft and allowing temperatures to warm slightly in the 50s and
perhaps some lower 60s by Tuesday. Minimal precipitation chances
appear in guidance through Thursday as surface high pressure is
present throughout much of guidance. The one caveat to this may come
on Wednesday morning as a weak 500mb wave with some associated
vorticity advection sneaks off to our east. Overall, ensemble
guidance is not overly enthusiastic about this potential though as
the grand ensemble (GEFS/EC/Canadian ensemble) has very low
probabilities (0-30% chance) for any measurable rainfall during
this period.

Upper-level ridging builds in again Wednesday night and into early
Thursday prior to fairly decent agreement on an upper-level
shortwave trough ejecting towards the Upper Midwest late week and
into next week. Still some fairly large disagreements between
deterministic models and their respective ensemble groups in how
this trough behaves, however the grand ensemble (GEFS/EC/Canadian
ensemble) does broad brush some higher probabilities (50-80%) for
measurable precipitation for late Thursday through next weekend so
seems like a decent signal for some precipitation during that
timeframe. As a result, have maintained the precipitation
chances (20-40%) Thursday night and into Friday from NBM.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 555 AM CDT Sat Nov 1 2025

The current widespread MVFR to IFR ceilings gradually improve
later this morning and afternoon to VFR by the evening. Light
showers likewise slowly decrease in coverage through the day as
they sink to the south. Light northwest winds early this
morning switch to north to northeast at 5-10 kts for the
daytime, becoming light and variable in the evening before
increasing out of the south towards sunrise on Sunday. Can`t
rule out fog along and east of the Mississippi River tonight,
but will be dependent on how fast clouds clear out this
evening.

&&

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

&&

$$

DISCUSSION...Naylor
AVIATION...Skow