000
FXUS63 KARX 262336
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
636 PM CDT Sun Jun 26 2022

.DISCUSSION...(This evening through Sunday)
Issued at 309 PM CDT Sun Jun 26 2022

Key Messages:

 - Cool and clear tonight, slowly warming through midweek.

 - Light showers possible Monday afternoon.

 - Better chance of storms (possibly severe) on Tuesday and
   Thursday.

The Work Week: Warming Temperatures

A cool and clear night is on the docket for tonight as surface
ridging builds into the region. Daytime CU should dissipate
shortly after sunset with temperatures tumbling into the 40s to
low 50s for lows. Given the dry air mass in place, would not be
surprised to see a few upper 30s in the valleys of SW Wisconsin.
The ridge axis passes east of the area by midday Monday, with
steady positive theta-e advection ongoing through the next 36
hours. Highs on Monday should nudge into the upper 70s/low 80s and
inch towards the low to mid 80s for Tuesday. Despite a cold front
dropping through Tuesday night, the boundary surges northward
Wednesday morning on a wave of strong WAA, pushing highs into the
mid to upper 80s. Thursday looks to be the warmest day of the week
as temperatures nudge towards 90 degrees just ahead of the front
dropping southward once again to end the week.

Monday: Chance of light showers

The initial wave of positive theta-e advection on Monday
afternoon coincides with peak heating and subtle height falls
ahead of a weak upper level shortwave working through the
northwesterly flow. The 26.12Z HREF guidance members are all
depicting some semblance of convective initiation along this
ribbon of theta-e advection. Weak effective shear and marginal
instability should result in transient and poorly organized storms
structures. A deeply mixed BL to 800 mb and 10-15 C dewpoint
depressions will further act to erode any precipitation generated
with these cells. Therefore, only added the mention of sprinkles
to the forecast for the afternoon. Cannot rule out a rumble or two
of thunder with any strong cells, but overall impacts look to be
low.

Tuesday/Thursday: Threat for Strong Storms

A progressive upper level pattern results in a vort lobe rotating
southeastward into the northern Great Lakes region Tuesday
afternoon. A weak frontal boundary sags southeastward in response
to the falling heights, reaching central Wisconsin towards 00Z
Wednesday. Baroclinicity along the front looks to be marginal at
best with only weak return flow off the lower Missouri River
valley nudging dewpoints towards 60 degrees. Clockwise turning
hodographs and modest effective shear values would be supportive
of organized cell structures, the question really hinges on how
much instability there will be to realize. The storm threat would
shift from north to south across the forecast area during the
afternoon, with the best threat for strong to severe storms being
from southeast Minnesota to southwest Wisconsin.

Another round of storms is likely on Thursday attendant to a
second cold front. At this time, there is ample uncertainty with
the placement of the front and the thermodynamic profiles ahead it.
It will be worth watching in the coming days. Looking ahead to
the holiday weekend, the start of the weekend looks to be dry, but
confidence towards Sunday and Monday degrades given the
progressive pattern.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 636 PM CDT Sun Jun 26 2022

With the loss of diurnal heating the northwest will quickly
drop to less than 10 knots between 27.02z and 27.04z. In addition,
the scattered 6-7K cumulus clouds will quickly dissipate.

As diurnal heating develops on Monday morning, a scattered to
broken 5-7K deck of clouds will develop across the area. The
CAMs have a few scattered showers in the area. However, with very
shallow moisture located across the region, there are plenty of
questions on where and even if they will develop.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&

$$

DISCUSSION...Skow
AVIATION...Boyne