La Crosse, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

499
FXUS63 KARX 282319
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
619 PM CDT Sun Jun 28 2026

.KEY MESSAGES...

- Hot and humid conditions arrive Monday and continue through
  much of next week with heat indices generally in the 95 to 105
  degree range, with Monday and Tuesday being the hottest as
  high temperatures will be in the mid to upper 90s and heat
  indices in the 100 to 110F range.

- Periodic shower and storm chances are possible each day this
  week.

&&

.DISCUSSION...
Issued at 213 PM CDT Sun Jun 28 2026

Today: Storm Chances?

An MCS moved through the area this morning and early afternoon
producing widespread rainfall. The better rain amounts were in
portions of northeast Iowa. As a result of this MCS, the anvil
continue to remain over the forecast area. Over the past hour or
so this anvil has slowly shifted eastward, leaving our western
tier of counties outside of the anvil influence. Outside of our
forecast area in northwest and west central Iowa, billow clouds
(indicating a stable environment) have morphed into a cumulus
field (indicating a potentially more unstable environment). Over
the past hour, this transformation has continued to move into
central Iowa as the anvil shifts off to the east. This warm
front will shift northward throughout the rest of the day. The
question for today is if the ridge that is going to be
amplifying throughout the day will keep the area capped off from
storm development, or if the warm front will be enough for
storm initiation. Current NBM hourly PoPs have a 15 to 30%
chance for storms this afternoon and early evening to highlight
this potential, before increasing later this evening as moisture
transport increases. If a strong enough storm can occur then
damaging winds or large hail would be the most likely hazard
type. Most CAMs are highlighting this evenings convection which
is focused north of I-94 for the evening before eventually
pushing north of the forecast area after midnight. In addition,
due to the anvil overhead temperatures will likely be a little
cooler than what is currently forecasted.

Monday-Friday: Hot and Humid Conditions, Periodic Storm Chances

Ensemble and deterministic guidance continues to show the ridge
amplifying off to our east and then staying over the eastern
CONUS through the week. This leaves our area in southwest flow,
which will push hot and humid air into the Upper Midwest through
the rest of the week. The 850mb temperatures for Monday will be
the warmest of the week with temperatures in the 23 to 26C
range, which will translate to high temperatures in the mid to
upper 90s. Dewpoints will be in the mid 70s through the week,
which for tomorrow means that heat indices will be in the 100 to
110F range. An Extreme Heat Warning is in place for Monday
through Tuesday for these heat indices. Tuesdays heat indices
are a little lower than Monday but still in the 100 to 105F
range. There will also be poor overnight recovery as
temperatures remain in the mid to upper 70s, which is the
reasoning for the continuation of the Extreme Heat Warning from
Monday through Tuesday. Southwest flow continues for the latter
portions of the week which will help high temperatures stay in
the low to mid 90s and heat indices stay in the mid 90s to low
100s.

Each day this week there is a wave moving through the Upper
Midwest which could help initiate storms. With the amount of
instability available each day coupled with each wave, there is
some severe storm potential every day. CSU ML probabilities have
our area in a 15% chance for severe weather every day until
Sunday. The main uncertainty is how capped the environment will
be each day. The first storm chance is Monday evening as a cold
front moves southeastward across the CWA. At the same time a
low-level jet increases (40 to 50 kts) which could help initiate
storms. One thing these storms could do is lower the heat risk
for the any given day as cloud cover from the storms could lower
the temperatures enough to be outside of any heat headline
being issued.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 619 PM CDT Sun Jun 28 2026

MVFR cigs will likely persist across much of the region through the
evening and into the overnight as low-level moisture remains locked
in place due to a warm frontal passage. As this front passes through
the area this evening, showers and some storms will be likely near
and north of I-90 which may reduce visibilities to MVFR and possibly
IFR levels underneath any storms. A couple of storms may be strong
with small hail and gusty winds, especially north of I-94. MVFR cigs
will begin to disperse during the daytime hours on Monday as diurnal
mixing begins with winds increasing to 15-20 kts by afternoon with
gusts up to 30 kts from the south.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Extreme Heat Watch from Monday afternoon through Tuesday
     evening for WIZ032>034-041-042-053>055-061.
MN...Extreme Heat Watch from Monday afternoon through Tuesday
     evening for MNZ079-086>088-094>096.
IA...Extreme Heat Watch from Monday afternoon through Tuesday
     evening for IAZ008>011-018-019-029-030.

&&

$$

DISCUSSION...Cecava
AVIATION...Naylor