154
FXUS63 KARX 301846
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
146 PM CDT Fri Oct 30 2026

.KEY MESSAGES...

- Scattered light showers over northeast Iowa and southwest
  Wisconsin spread northward through Halloween morning before
  diminishing during the afternoon and evening.

- More widespread and longer duration rainfall is expected next
  week (80-95%), bringing the potential to exceed 1 inch of rain
  (40-60%).

- Temperatures trend warmer this weekend into early next week
  before cooling back towards normal for the latter half of the
  week.

&&

.DISCUSSION...
Issued at 146 PM CDT Fri Oct 30 2026

This Afternoon - Sunday: Scattered Light Showers, Trending Warmer

Isolated to scattered showers continue across portions
northeast Iowa and southwest Wisconsin this afternoon associated
with an area of 925-850hPa warm air and theta-e advection.
These showers should largely stay along and south of the
Minnesota/Iowa border given drier air present below 10kft to the
north, though can`t rule out some sprinkles up to I-90 as we
head into the evening. Elsewhere, cloud cover will continue to
increase, but dry conditions are expected. Where showers do
develop, moisture is fairly shallow so amounts should only be a
few hundreths of an inch.

Light showers increase in coverage overnight as a 700-500hPa
shortwave trough across Texas lifts northward atop the
previously mentioned lower level forcings, coinciding with a
stronger northward surge of low level moisture. While coverage
will still largely be scattered, much of the Upper Mississippi
River Valley should see some light rainfall through Saturday
morning (50-70%), most likely across northeast Iowa and
southwest Wisconsin where deeper moisture remains. Still not
expecting a washout, but if some elevated instability noted in
RAP soundings (100-200 J/kg) can be realized, some rumbles of
thunder and localized rainfall amounts up to 0.3 inches are
possible (30-50%).

The low level forcings move into northeast Wisconsin Saturday
afternoon and evening, resulting in diminishing showers and some
drier trick-or-treating conditions across our area. That said,
can`t rule out some residual light showers lingering into
Sunday morning as various bits of shortwave energy slowly
meander through the Upper Midwest, but mostly dry conditions
should briefly return Sunday afternoon and evening. Given
persistent southerly winds throughout the weekend, expect a
warming trend as we head into the new week with high
temperatures in the low to mid 60s by Sunday, around 10 to 20
degrees above normal.


Monday - Wednesday: Widespread Rainfall, Continued Warmth

Heading into next week, longwave troughing over the western
United States moves eastward into the central Great Plains while
a shortwave trough dives southward out of Canada. These
features are expected to produce a fairly stout surface low
pressure system that lifts northeastward into and through the
Upper Midwest. At this point, it looks to be a near certainty
(80-95%) that we will see rainfall across the Upper Mississippi
River Valley given substantial QG forcing associated with these
features.

To coincide with the forcing, an impressive northward surge of
moisture is expected as the low lifts northward. The 30.00z
NAEFS/EPS suggests PWATs should be above the 99th percentile of
climatology, and even indicate they could be above the
climatological maximum. That is to say, the atmosphere should
be fairly juiced up for some efficient rainfall, but where this
moisture ultimately ends up, and by association the greatest
rainfall amounts, is a bit in question. The majority of the
ensemble guidance (GEFS/EPS/GEPS and their AI equivalents)
depict the axis of heaviest rainfall to our west closer to the
current favored track of the low, but there are some members
that trend the low further eastward which would result in higher
rainfall amounts across our area. The 10th-90th spread of
rainfall amounts in the 30.13z NBM is large at this point given
the uncertainty of the low`s track, but probabilities currently
favor at least 1/2" (70-90%) and are fairly high for 1+"
(40-60%). Otherwise, above normal temperatures continue through
midweek before trending cooler behind the departing low.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1245 PM CDT Fri Oct 30 2026

Light rain showers continue across portions of northeast Iowa
and southwest Wisconsin this afternoon before lifting northward
overnight, becoming more widespread across the region through
much of the day Saturday. Ceilings also begin to lower towards
MVFR during this time while sites in northeast Iowa and
southeast Minnesota may see ceilings fall below 1kft (30-50%).
Conditions begin to improve late Saturday as the rainfall
diminishes and moves into northeast Wisconsin. Winds will be
predominantly from the southeast between 5-10KT through the TAF
period.

&&

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

&&

$$

DISCUSSION...Falkinham
AVIATION...Falkinham