850
FXUS63 KARX 261822
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
120 PM CDT Fri Jul 26 2024

.KEY MESSAGES...

- Summer heat/humidity return this weekend, hanging around for much
of the new week. Highs from the mid 80s to around 90 with heat
indices about 5 degrees warmer expected.

- Shower/storm chances return for Sun/Mon. Locally heavy rain
possible.

&&

.DISCUSSION...
Issued at 120 PM CDT Fri Jul 26 2024

OVERVIEW: Upper level ridge sits overhead today and is still on pace
to slide east over the weekend. The upper level flow then shifts to
broad ridging for the new week, a consistent signal in both the GEFS
and EPS. Warmer, more moist air pools northward under the ridge and
a return to "summery" air should be planned for this weekend,
through most/if not all of the new week. The pattern shift will also
allow for shortwave troughs to have a better opportunity to spin
near/through the area - and rain chances return to the forecast as a
result.

How long the broad ridging holds is a question. Some mixed messages
between the GEFS and EPS suite of members, which shows in the latest
run of the WPC cluster analysis. The bulk of the EPS members hold
onto the broad ridging through the weekend while more of the GEFS
suite suggest reamplification of the west coast ridge. Sensible
weather outcomes would be a continuation of the warmth in the EPS
but cooler/less humid via the GEFS. A fair amount of volatility in
the models that far out at this time, keeping confidence low in
which way to trend. That said, there does seem to be more support to
hold the broad ridging pattern trough the weekend. We`ll see...


TEMPS: say "hello" to summer, she`s back. Warmer, more moist air
will start to pool northward this weekend and settle in for the new
week. The EPS suite continues to be the warmest of the long term
guidance with 75% of its members pushing high temps into the upper
80s/lower 90s. GEFS is a few/several degrees cooler - but still at
or above the late July/early August normals. With dewpoints expected
to climb into the upper 60s to lower 70s, tack on at least another 5
degrees for what it will "feel like" (heat index). Not currently
trending hot enough where headlines would be needed (heat
advisories), but certainly ample enough heat that those with outdoor
plans should prepare for it. More uncertainty moving into next
weekend with the differences in the models sending mixed messages.


RAIN CHANCES: med/long range guidance continues to spin bits of
shortwave energy northeast across the region for Sun/Mon as the
ridge exits east. Kind of a hodgepodge of pieces of energy which may
or may not coalesce into one more cohesive (and stronger) shortwave.
Still, mix of forcing and favorable airmass look to trigger areas of
showers/storms Sun through Mon. PWs upwards 2" and warm cloud depths
near 4 kft suggest a locally heavy rain potential. Strong/severe
risk is more nebulous with timing of the system(s) playing a larger
role. There will be instability to work with but deep layer shear
may hold farther west.

After Monday, the models show a variety of potential rain makers
for the region, with differences in timing/placment/strength. Which
day(s) harbor the higher chances aren`t clear and will roll with the
model blend for now.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1224 PM CDT Fri Jul 26 2024

Some 925 and 850 mb moisture will remain over the forecast area.
This will result in a scattered to broken deck of 2500 to 5000 deck
of clouds. The greatest concentration of clouds will be west of the
Mississippi River through tonight. These clouds then gradually shift
east late tonight and Saturday. South and southeast winds will
remain generally less than 10 knots.

&&

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

&&

$$

DISCUSSION...Rieck
AVIATION...Boyne