669
FXUS63 KARX 040834
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
334 AM CDT Fri Jul 4 2025

.KEY MESSAGES...

- Showers and storms exit west-central WI early this morning.
  Additional showers and storms likely (60-80%) tonight and
  into Saturday.

- Hot for today with daytime heat indices in the 90s to near 100
  degrees. Heat indices may top 100 degrees in some locations
  north of I-94 and in river valley locations.

- Seasonable conditions with intermittent chances for showers
  and storms next week.

&&

.DISCUSSION...
Issued at 334 AM CDT Fri Jul 4 2025

Today: Hot, Showers & Storms Exit This Morning

Showers and storms have developed and moved through portions of the
local area early this morning. Overall, heavy rain leading to some
localized flash flooding remains the primary concern as portions of
western Jackson County where upwards of 3-5" of rainfall have fallen
thus far based on MRMS totals. Continued expectation keeps some
stratiform rain over this area through the early morning,
however cannot rule out some discrete convection working its way
into west-central WI from the northwest towards sunrise.
Regardless, much of the CAMs generally agree on maintaining off
and on showers/storms across west-central WI before fizzling out
by 6-8am.

As we head into the afternoon, upper-level ridging will sneak in
from the south with some subsidence along with it. Consequently,
expecting some clearing in our skies which coupled with dewpoints in
the lower 70s will allow heat indices to reach into 90s to near 100
degrees for the afternoon hours. Overall, does not appear to be an
excessively warm airmass as the 03.12z EFI only has 60-70%
probabilities for our area to exceed model climatology for maximum
temperatures this afternoon. Regardless, with heat indices in the
90s to near 100 expected in combination with ongoing activities for
the 4th of July, be sure to be cognizant of those who may be
vulnerable to the heat and take breaks as needed when outdoors.

Tonight - Saturday: Additional Showers & Storms Likely

Looking towards the overnight hours for tonight, a 500mb shortwave
trough with an accompanying surface low will push in the Upper
Midwest. As this occurs, a nice axis of 850mb moisture transport
will push northward into the region. Overall, the generally evolution
of precipitation during this period would favor having convection
popping up along and ahead of the attending frontal boundary with
the surface low throughout the day on Saturday. It seems likely we
will see some healthy rainfall during this period as the recent
04.00z HREF has decent probabilities (30-80%) that much of the area
will see 0.5" of rainfall or greater. Locally higher amounts of 1-2"
or greater will be possible depending on where convection tracks
over. Eventually as the boundary pushes from west to east through
the evening and overnight hours, precipitation chances will quickly
diminish from west to east.

As far as any severe potential with this on Saturday, instability
values are fairly respectable with MLCAPE values ranging from 1000-
2000 J/kg throughout the day. However, the lack of strong flow aloft
will likely keep bulk shear values to a minimum which should limit
organization to being along any cold pools which would favor pulse-
like single-cells to multicellular convection. As a result, thinking
that isolated strong wind gusts may be possible with some wet
downburst potential as precipitable waters range from 1.5-2" and
instability profiles are generally more skinny which would favor
some precipitation loading in any stronger cores. Otherwise, any
severe potential would appear to be fairly limited.

Sunday & Next Week: Seasonable, Intermittent Shower & Storm Chances

By Sunday, subsidence behind the aforementioned 500mb trough will
aid in seeing some clearing skies and brief northwesterly flow
will keep temperatures pleasant for Sunday with highs in the
upper 70s to middle 80s across the local area. Quasi-zonal flow
returns for the early part of next week which in turn will bring
some risk for showers and storms with any embedded pieces of
shortwave energy. Consequently, have some precipitation chances
throughout the upcoming work week, however confidence in how any
shower and storm chances will manifest with these remains low at
this time.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1240 AM CDT Fri Jul 4 2025

VFR conditions should prevail over the next 24 hours along and
west of the Mississippi. To the east of the Mississippi and
north of a Y51 to 82C line, scattered thunderstorms will affect
the area through 12z with occasional reductions to IFR
conditions as these storms occur. TS should remain greater than
5 miles from LSE but may skirt the 10 mile radius, so have
included VCTS at this site for the first 90 minutes of the TAF
period. Once TS shifts southeast Friday morning, confidence is
fairly high in VFR conditions with little (<5%) concern for
additional TS until after the end of the period.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Heat Advisory from noon today to 8 PM CDT this evening for
     WIZ017-029.
MN...None.
IA...None.

&&

$$

DISCUSSION...Naylor
AVIATION...Ferguson