022
FXUS63 KARX 081037
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
537 AM CDT Mon Jun 8 2026

.KEY MESSAGES...

- Muggier today with numerous showers and storms, producing
  widespread rainfall amounts of 1-2 inches with locally higher
  pockets exceeding 3 inches.

- Increasing heat and humidity into mid-week. Highs in the low
  90s are likely (70 to 90% chance) for Tuesday and Wednesday
  but recent forecast runs have trended a smidge cooler.

- Increasing likelihood for a severe weather event, potentially
  significant, Wednesday afternoon-evening with large hail,
  damaging winds, and tornadoes possible. Many forecast details
  still uncertain.

- Conditional severe weather risk in our far southeast on
  Thursday depending on how Wednesday`s event evolves.

&&

.DISCUSSION...
Issued at 100 AM CDT Mon Jun 8 2026

Today: Muggy with Showers and Storms, Locally Heavy Rain

A shortwave trough lifting in from the southwest combined with
weak low level moisture transport will contribute to renewed
fairly widespread shower/storm chances across the area today
into this evening. As the moisture transport axis becomes more
south-north oriented, a rich plume of precipitable water will
increase overhead this morning to around 2 inches, with
dewpoints climbing to around 70. It is noteworthy that warm
cloud layer depths today are also on the increase to around 4km,
so the deep saturation through the column along with
tall/skinny CAPE profiles will favor heavy rainfall potential
with any more robust convection.

Storm motion should be a little faster compared to yesterday
due to the shortwave pushing through, so it is less likely to
have heavy rain stall over an area. However, if storms repeat
over any areas, particularly those in northeast Iowa and
southwest Wisconsin that were recently saturated by heavy rain
in the past 72 hours, there could be a quicker runoff response
that could potentially lead to localized flooding. HREF max 24
hour rainfall suggests pockets of 2 to 5" rainfall is not out of
the question, mainly over western Wisconsin. Given the limited
instability (up to 1000 J/kg SBCAPE) and weak shear profiles,
severe storms are not expected from today`s convection.

Tue - Wed: Heat and Humidity Briefly Build In

Upper level ridging will build behind the departing shortwave
trough beginning Monday night and continuing through Wednesday.
This sets us up for the long-advertised but brief hot spell
Tuesday into Wednesday. Recent NBM runs have shown a slight
downward trend in the potential for max temps reaching 90+ owing
to some questions around cloud cover and Wednesday`s
precipitation chances. But by Wednesday the NBM mean has
widespread low to mid 90s. GEFS and ENS both lend very high
confidence (>90%) for dewpoints nearing or exceeding 70 for the
majority of the area Tuesday and especially Wednesday, creating
sticky, humid conditions. Heat indices on Tuesday look to reach
into the 90s with values of 95-105 for Wednesday, again
conditional on how clouds and storms unfold.

Wed Afternoon/Evening: Severe Storms, Potentially Significant

The heat and oppressive humidity will break heading into
Thursday, but not before a potentially significant severe
weather setup Wednesday afternoon-evening. Deep longwave
troughing digging into the Northern Plains and eventually Upper
Mississippi Valley will drive a strong cold front into the
region heading into Wednesday evening. The magnitude of severe
weather will hinge on the exact timing of this front and
resultant impacts on available instability. Frontal passage in
the late afternoon to early evening hours would encounter SBCAPE
on the order of 2500-3000+ J/kg (per GEFS/GEPS), whereas a
delayed arrival into the evening would mean less instability to
work with.

There does look to be ample deep layer shear near the front of
40+ knots to support supercells with hodographs showing
pronounced clockwise curvature in the 0-1km layer. All severe
storm hazards will be in play, but their likelihood will depend
on storm mode details that will be pinned down over the next
couple days. Will also have to watch to see if any convection
Tuesday night into Wednesday morning might spoil the severe
weather setup for later in the day.

Thursday: Conditional Severe Weather Threat in NE IA & SW WI

By Thursday morning, the cold front will stretch from the
Central Plains into the Upper Great Lakes with potentially a
developing surface low riding northeast along it. This should
focus the bulk of convective activity just to our southeast, but
far northeast Iowa and southwest Wisconsin could be on the
fringes depending on exactly where the front sets up. By
afternoon, our southern tier of counties could be on the SBCAPE
gradient with rich deep layer shear in place, supportive for
some additional severe weather potential. In short, Thursday`s
severe potential will be conditional, hinging on how Wednesday`s
event evolves.

End of the Week into the Weekend: Cooler

Periodic small shower and storm chances dot the extended
forecast into the weekend, but by Sunday into next week deep
upper troughing looks to bring a flip to below normal
temperatures.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 536 AM CDT Mon Jun 8 2026

Widespread showers and isolated thunderstorms move through the
region through mid to late afternoon today. Ceilings fall to
MVFR/IFR during this time, with the higher probabilities of IFR
ceilings (60-80% chance) west of the Mississippi River before
15Z today. Pockets of IFR visibilities will occur with any of
the stronger showers. This system departs in the late afternoon
and evening, and depending on how fast clouds depart, a
widespread IFR/LIFR fog looks to develop overnight into Tuesday
morning. Winds through midday will be from the southeast at
5-10kts, become lighter and more variable during the afternoon
into the overnight.

&&

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

&&

$$

DISCUSSION...Kurz
AVIATION...Skow