479
FXUS63 KARX 281059
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
559 AM CDT Tue Jul 28 2026

.KEY MESSAGES...

- Warm temperatures continue this week with highs mainly in the
  80s, but dewpoints staying largely in the 60s.

- Next storm chances come late week. Severe threat looks low
  with the main hazard being heavy rainfall.

&&

.DISCUSSION...
Issued at 1232 AM CDT Tue Jul 28 2026

Today - The Weekend: Warm Temperatures Continue, Rain Chances
Return Later in the Week

After a couple of hot and humid days, the ridge that has been
sitting over the CONUS for awhile now, shifts ever so slightly
westward. This will keep the area in northwest flow aloft. A
surface high also moves over the region. Both of these will help
keep those upper 70s and mid 80s dewpoints away and keep the
area mostly dry through Wednesday. There have been some models
that try to bring some shower or storm activity into west-
central Wisconsin and eastern Minnesota late Wednesday afternoon
as the surface high shifts eastward allowing for enough
instability, 1000 to 2000 J/kg of MUCAPE from the 00Z HRRR, to
build in. There are some ensemble members that support
measurable precipitation across these areas on Wednesday,
however not much looks to expected for rain amounts.

Heading into Thursday/Friday a more defined shortwave trough
that moves into the Upper Midwest. This trough becomes closed
off as it shifts more over our CWA by Friday morning. At the
same time, the low-level jet increases overnight Thursday into
Friday. Moisture transport is also good as this jet will have a
fetch all the way from the Gulf allowing for PWATs to be in the
1.75 to 2.0" range. This low then moves off to the east by
Friday evening. While there are still timing differences, this
has the potential for heavy rain to occur. There are a few GEFS
and EPS members that have 3+ inches of rain over parts of the
CWA. WPC has went ahead and put the majority of our forecast
area in a slight risk for excessive rainfall as a result of the
parameters in place. All this being said, this will be something
to watch as we get closer to Thursday.

Temperatures over the next couple of days remain in the mid
80s, however the dewpoints will be a bit lower than what we have
experienced over the last few days, mainly in the 60s.
Depending on the track of the low on Friday, temperatures could
be on the cooler side if it rains for much of the day. Once this
low is out of the Upper Midwest, temperatures look to rebound
back into the mid 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 556 AM CDT Tue Jul 28 2026

Outside of some patchy low clouds around 1.5-2kft across
central to southwest Wisconsin this morning, VFR conditions are
expected across the region throughout the day. Light north to
northeast winds this morning become variable this afternoon and
overnight as high pressure moves through the region. Skies are
expected to clear as the high moves through, leaving clear to
mostly clear skies tonight. Combine these clear skies with the
light winds associated with the aforementioned high pressure,
there does appear to be some potential for valley fog to develop
tonight primarily in the fog prone valleys such as the
Wisconsin River Valley. The 28.07z NBM currently has the
strongest signal fog potential, suggesting 20-30% probabilities
for 3SM or less across southwest Wisconsin while the 28.00z HREF
and 28.06z REFS suggest < 10% probabilities for 3SM
visibilities or less.

&&

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

&&

$$

DISCUSSION...Cecava
AVIATION...Falkinham