794
FXUS63 KARX 061733
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1233 PM CDT Fri Jun 6 2025

.KEY MESSAGES...

- Cooler with light rain today, mainly during the morning and
  early afternoon hours. A thunderstorm cannot be ruled out
  (15% chance) this afternoon.

- Saturday through Monday bring at least three rounds of
  rain and potential (20-30%) embedded thunder. Amounts across
  these days will tend to be modest (around 1" or less).

- Warmer conditions are favored for the middle part of next week
  with highs looking to climb back into the 80s. Rain may return
  Thursday night.

&&

.DISCUSSION...
Issued at 342 AM CDT Fri Jun 6 2025

Light rain with low chance for thunder today:

Surface obs and radar show a large portion of the CWA is
experiencing light rain as of 07z as lift occurs ahead of a weak
shortwave in the presence of shallow mid-level moisture (as
evidenced by the widespread clouds in the 5-10 kft layer seen on
satellite) with most locations seeing only a few hundreths.

Today, additional light rain should occur as another wave, currently
located over SE SD, ejects eastward. As is usually the case, NBM is
struggling mightily with PoPs in this low QPF scenario, suggesting
only about a 20-40% chance for rain, even in the immediate term when
rain is clearly occurring. Have moved PoPs toward depiction seen in
06.01 through 06.06z HRRR runs with light rain likely occurring this
morning into early this afternoon with an additional round possible
in SW WI this evening as subtle lift occurs in the right entrance
region of an upper jet. As for thunderstorms, progged soundings
suggest only modest instability will be present - 06.00z HREF
probabilities for at least 250 J/kg are generally 0-40% - so have
kept thunder mentions to a slight chance (20%).

Periodic rain Saturday through Monday:

Additional light rain may occur during the day Saturday,
particularly in NE IA and SW WI as the upper wave responsible and
thus the majority of the forcing for lift look to pass to the south
of the forecast area.

Saturday night into Sunday morning will very likely (60 to 90%) see
rain across much of the forecast area as an upper low dives
southeast out of Canada while a stout upper wave rotates around this
feature. Given the cooling temperatures aloft, some embedded
thunderstorms will be possible during this period (20%). While
amount of forcing is impressive and the increase in winds aloft
leads to sfc-6km bulk shear values to around 50 knots, the arrival
of this wave very early Sunday suggests instability will be greatly
limited. Thus, unless the arrival of this wave slows considerably,
severe thunderstorms are not expected.

A third round of showers will occur Monday as the main body of the
aforementioned upper low moves overhead. Once again, this feature
looks to be departing to our east before appreciable instability can
develop via surface insolation. Thus, while lapse rates should once
again be steep enough for sporadic thunder due to mid-level cooling,
severe thunderstorms appear very unlikely.

Despite the likelihood of multiple rounds of rainfall over the next
72 hours, overall moisture in the atmosphere appears limited.
Progged PWAT values in both the 06.00z NAEFS and 05.12z ECENS are
around average compared to climatology. The end result is a small
(10-40%) to exceed 1" in total accumulation across the next 72
hours. Thus, in addition to only scant potential for severe
thunderstorms described above, excessive rainfall and flash flooding
appear highly unlikely.

Warmer by mid week

After a below normal Tuesday as the upper low departs to the east,
heights aloft look to build with 06.00z GFS/EC/CMC suggesting these
will be maximized next Thursday afternoon. This may result in
temperatures returning to the 80s. However, hints toward a weaker
ridge aloft noted in previous discussion continue in the latest
suite of guidance with potential for an upper trough to lift
northeast out of MO and bring some additional rain Thursday night
and potentially bring an end toward the warming trend next Friday.
All that said, at this time, nothing stands out as a potential
weather hazard during this period of the forecast.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1234 PM CDT Fri Jun 6 2025

A weak trough will move east across the area this afternoon.
This will result in the potential for isolated to scattered
showers. As a result, the PROB30 in the current TAFS look good.
There may be a few isolated storms, but confidence was far to
include them in the TAFs at this time.

&&

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

&&

$$

DISCUSSION...Cecava
AVIATION...Boyne