146
FXUS63 KARX 171848
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
148 PM CDT Thu Jul 17 2025

.KEY MESSAGES...

- Cooler temperatures and mostly dry conditions today and Friday
  with temperatures in the lower 70s today and mid to upper 70s
  for Friday.

- An unsettled pattern is setting up from the weekend to the
  middle of next week with several chances for rain. Next
  widespread rain chance (40 to 70%) is Friday evening through
  Saturday morning.

- Temperatures will gradually warm back up into mid to upper
  80s by Wednesday

&&

.DISCUSSION...
Issued at 134 PM CDT Thu Jul 17 2025

Today - Friday: Cooler and Drier

It almost feels reminiscent to fall out there today with a much
cooler and drier airmass in place across the Upper Midwest.
Temperatures this morning dropped into the 50s for most with a few
locations dipping into the upper 40s. Dew points across the area
have also been on the decline with north/northeasterly winds pushing
them down into the lower 50s. Scattered low clouds are lingering
for some areas as the deeper dry air lags behind the immediate
low level push. Highs this afternoon will be at their coolest
in a while in the lower 70s. Overnight lows tonight will be
comparable to last night with most places in the 50s. Given the
mostly clear skies expected and drier airmass, some places along
and north of I-94 could drop into the mid and upper 40s,
especially in the notorious cold spots of the West Central
Wisconsin Cranberry Bogs. Have blended some NBM 10th percentile
lows into these areas to better reflect this possibility.
Tomorrow will start the gradual warm up back to near normal
temperatures with highs in the mid to upper 70s and increasing
clouds through the afternoon.

Friday Night - Mid Next Week: Unsettled Pattern Returns,
Warming Up

A weak mid-level trough is expected to work its way into the
northern Great Plains tomorrow afternoon, setting off some
storms across eastern South Dakota, southern Minnesota, and
northwestern Iowa. There remain significant CAM differences in
how these evolve tomorrow but many models grow these storms
upscale into an MCS. Now where this propagates is still highly
uncertain but the general consensus for now would be more
easterly across the I-90 corridor. With increasing southerly
flow into these storms providing even more abundant moisture,
these storms will likely be efficient rainfall producers. By the
time they reach our area, likely late overnight Friday into
Saturday, they should be more progressive in nature but given
the abundant rainfall we`ve already seen across our area, most
of this would have the potential to runoff and create some
ponding/flash flooding concerns. As such, WPC has highlighted
along and south of the I-90 corridor in their Day 2 Slight Risk
for excessive rainfall. In addition, there is some concern that
this MCS could have a marginal damaging wind threat through the
overnight hours as capping will be weak and a LLJ around 850 mb
across Iowa should keep it sustained enough for isolated
instances of damaging winds. Hopefully we`ll start to get better
CAM consistency with the upcoming 18.00 suite but for now,
western portions of our area (SE MN and NE IA) remain in the Day
2 Marginal Risk for severe weather.

Strong ridging to our south will keep our area in zonal flow
through the weekend. Shortwave impulses are expected to traverse
the flow aloft, helping to initiate some storms across the area
most days. PoPs each day Saturday through mid next week are
generally in the 20-40 percent range with the best chances each
day expected near the baroclinic zone. As this is not well
resolved this far out, will leave the broadbrushed PoPs as is
for now.

The upper level ridge is expected to become a bit more defined over
our area by mid-next week as an upper trough moves into the western
Canadian provinces. How this trough evolves is still a bit murky but
this does make the upper level flow a bit more meridional by Monday
with our area in the crest of the ridge. And while this won`t shut
off rain chances, this will work to increase highs with anomalously
warm temperatures building into the 850-700mb region. Highs
will be warmest across our southern counties, which should be
more firmly under the influence of the ridging. Highs by
Wednesday will be back into the upper 80s to around 90 with
muggy conditions and dew points in the lower 70s. Enjoy the
cooler temperatures today because summer will not be gone for
long.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1207 PM CDT Thu Jul 17 2025

VFR conditions expected for the next 24 hours. Scattered clouds
at FL025-040 will continue through the afternoon hours before
clearing out overnight. North winds will linger into this
evening with occasional gusts to near 18 kts at the terminals
possible this afternoon. Winds will become light and variable
overnight but should gradually veer to the south/southeast by
mid-morning tomorrow.

&&

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

&&

$$

DISCUSSION...Barendse
AVIATION...Barendse