231
FXUS63 KARX 162331
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
631 PM CDT Wed Jul 16 2025

.KEY MESSAGES...

- Showers and storms impact the region this morning through the
  evening. Some of these storms could be strong to severe in
  southwestern Wisconsin this afternoon with damaging winds
  being the main threat.

- Locally heavy rainfall is the main concern with these storms.
  Current forecast has a swath of 1 to 1.5 inches across the
  I-90 corridor, with some locally higher amounts possible.

- Cooler temperatures for the end of the week with highs in the
  70s and low 80s from Thursday through the weekend, then
  gradually warming up into the middle of next week.

&&

.DISCUSSION...
Issued at 146 PM CDT Wed Jul 16 2025

Today: Strong to Severe Storms, Heavy Rain

As of 1 PM, strong to severe storms on a line extending from
Sparta to the city of Monroe, WI continue to move northeast
ahead of a well defined MCV across far northeastern Iowa. Severe
storms will likely be focused along this line as the instability
gradient drops off significantly with the cold front beginning
to impede from the west. Locally increased low level shear from
the MCV could create a brief spin up as streamwise vorticity is
maximized along the quasi warm front but better conditions for
this reside further to our east across South Central Wisconsin.
This line will continue to push off to the east with the severe
threat for our area decreasing through the afternoon.

Of additional concern, these storms are producing very heavy
rain with rainfall rates in the 1-2"/hr range being reported
across many area mesonets with the passage of these storms. The
atmosphere is ripe with moisture with continued 925-850 mb
moisture transport into the area and pWats in the 1.75-2.25 inch
range. Warm cloud depths are approaching 3 km and corfidi
vectors are aligned with the mean wind which is allowing for
some training over the area. The good news is that this system
is very progressive overall so widespread flooding is not
expected to materialize but with the heavy rainfall rates, urban
and localized flooding will certainly remain possible with
these storms. 16.12Z HREF LPMM QPF totals remain concentrated
along the I-90 corridor as the deformation band sets up just
north of the surface low that is residing over the Tri-State
Region early this afternoon. Totals in the 1-3 inch range seem
reasonable for this area with isolated instances of 3+ inches
possible. Outside of the this corridor, .25-.75 inches seem more
likely given how transient the showers and storms have already
been. Rain chances will end through the afternoon for areas west
of the Mississippi River with areas to the east seeing some
isolated showers and storms into the evening.

Thursday - Friday: Cooler and Mostly Dry

As winds shift to the north behind the surface low/cold front,
cooler and drier air will begin to overspread the area. Dew
points are expected to drop into the 50s to low 60s by early
tomorrow morning with skies expected to clear from the
north/northwest. Temperatures tomorrow will be reminiscent of
early fall in the low to mid 70s as a weak surface high moves
overhead through the day. Conditions should remain dry through
the first half of Friday with some more rain moving in late in
the day.

Saturday - Mid-Next Week: Unsettled Pattern and Warming Back Up

Zonal flow aloft is expected to dominate our weather pattern as
a strong east/west oriented ridge holds firm across the
southern CONUS. Some shortwave impulses are expected to move
overhead, spurring some convective development. Current guidance
shows these impulses traversing our area Friday night/Saturday
with another Saturday into Sunday. At the surface, this looks to
take the form of MCSs that develop out to our west across the
Dakotas and ride the baroclinic zone that sets up into northern
Illinois. Given that these shortwave impulses are just starting
to enter the hi-res timeframe they should hopefully become a bit
more well defined for the upcoming packages. Have left the NBM
PoPs through next week with the highest chances (50-70%) coming
overnight Friday into Saturday and low end PoPs (20-30%)
continuing on and off through the midweek timeframe.
Temperatures will gradually warm back into the 80s through the
weekend with the warming trend continuing into the work week
with highs in the upper 80s to 90s by Tuesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 631 PM CDT Wed Jul 16 2025

Low-MVFR to IFR cigs will persist throughout much of the evening and
overnight before a low-level inversion begins wane after daybreak
which will result in a gradual increase to VFR conditions. IFR
cigs at KLSE will be possible (20-40% chance) this evening and
overnight at times, however per RAP soundings and probabilistic
in the 16.12z HREF favoring low-MVFR cigs, have opted to keep
low-MVFR mention for now. A stray shower cannot be ruled out
(~20% chance) at either terminal later this evening or tonight,
however minimal impacts would be expected. Winds will generally
remain between 5-12 kts from the north throughout the TAF
period.

&&

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

&&

$$

DISCUSSION...Barendse
AVIATION...Naylor