221
FXUS63 KARX 171758
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1258 PM CDT Fri Oct 17 2025

.KEY MESSAGES...

- Periodic showers and potentially (20-30%) a few thunderstorms
  are expected into Saturday night. Rainfall amounts for most
  will likely (60-100%) stay around or below 0.50 inches with
  some higher amounts closer to 1 inch possible (10-20%) across
  far southwestern Wisconsin.

- Warmer than normal temperatures are expected through Saturday
  ahead of a cold front. Seasonal, near normal temperatures
  return for next week.

- Gusty west to northwest winds will be possible Sunday through
  Tuesday as progressive pattern brings multiple systems
  through the area.

&&

.DISCUSSION...
Issued at 1253 PM CDT Fri Oct 17 2025

Today - Saturday: Off and On Rain Chances, Warm Temperatures

Highly isolated light showers are overspreading much of the
Upper Mississippi Valley ahead of a cold front draped north to
south across Minnesota, extending from a occluding surface low
across southern Manitoba. In the upper levels, a weakening upper
low is ejecting northeast towards the Hudson Bay with
southwesterly flow continuing across much of the Upper Midwest.
A jet max was located across much of Minnesota at 500 mb. This,
along with increasing convergence along the frontal boundary and
continued low level moisture transport into the area, will
allow for continued shower and weak storm development through
the afternoon and into the overnight hours tonight. Coverage is
expected to be more scattered in nature, largely due to the low
level warm air advection creating a capping inversion between
800-900 mb. This will also serve to limit instability with mean
MUCAPE values from the 17.12 HREF no higher than 250 J/kg across
the region. Rain chances will gradually shift east as the front
slowly progresses through the area with most rain chances
coming to an end by 12Z Saturday.

Rain chances are not totally over though as the trough axis lags
behind the upper low and doesn`t look to swing through our area
until around 12Z Sunday. Late Saturday, as the main body of the
trough moves in, some light rain chances look to overspread the
area. An axis of heavier rain will be possible across far
southwestern Wisconsin, where slightly better instability and lift
could co-locate overnight into Sunday. Overall instability forecasts
for Saturday have come down in the 12Z HREF but there should still
be enough for some heavier showers. QPF totals should stay at or
below 0.5 inches but there remains a low chance (less than 20%) some
locations across far Southwest Wisconsin could see totals around 1
inch before all is said and done Sunday morning.

Temperatures tomorrow will remain above average, though to a
slightly lesser degree than today. Highs will remain in the mid 60s
to lower 70s as the cold air advection doesn`t look to really kick
in until the trough axis swings through late Saturday into early
Sunday.

Sunday - Late Next Week: Progressive Pattern with Gusty Winds
Sunday Through Tuesday.

Dry conditions are expected to prevail across the area Sunday and
Monday with weak upper level ridging sliding in behind the exiting
trough. Sunday could see some gusty conditions as a rapidly
deepening surface low across the Great Lakes tightens the local
pressure gradient.  Temperatures both Sunday and Monday look to
return closer to normal in the mid 50s to mid 60s.

Attention quickly turns to the next trough and upper low that is
expected to drop southeast out of Canada Monday into Tuesday. Its
corresponding surface low is expected to deepen across North Dakota
and northwestern Minnesota before moving east into the Northern
Great Lakes. This will likely lead to continued gusty winds on
Monday and especially Tuesday on the backside of the departing
surface low. 17.12Z GFS soundings show the potential for deep mixing
Tuesday afternoon bringing potentially 40 kt gusts to the surface.
17.13 NBM probabilities show a 30-50 percent chance of gusts at or
above 40 mph across pretty much all of the Driftless Region for
Tuesday. This will be something to monitor in the coming days with a
wind headline potentially in the cards. Otherwise, the generally
progressive pattern looks to continue through the rest of next week
with off and on rain chances and temperatures moderating out in the
50s to low 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1245 PM CDT Fri Oct 17 2025

Primary aviation consideration over the next 24 hours will be a
broken line of showers that will develop over portions of the
region associated with a weak frontal boundary later this
afternoon and into the evening. Overall, probabilities for MVFR
reductions are not overly impressive (20-50%) in the recent HREF
guidance, however cannot rule out some vsby or cig reductions
with any heavier showers that pass through. Otherwise, mid-level
sky cover will gradually clear through the overnight leaving
mostly clear skies through daybreak on Saturday. Winds will
begin the TAF period from the south between 12-18 kts with
occasional gusts to 25 kts west of the Mississippi River.
However, winds will gradually decrease to under 10 kts this
evening and overnight.

&&

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

&&

$$

DISCUSSION...Barendse
AVIATION...Naylor