173
FXUS63 KARX 082330
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
630 PM CDT Wed Oct 8 2025

.KEY MESSAGES...

- Areas of frost in portions of western and central Wisconsin
  tonight and Thursday morning.

- Increasing shower chances (30-50%) Thursday night areawide.
  Rainfall amounts of under 0.1" are generally expected.

- Slight warming trend into the weekend and early next week with
  highs in the middle 60s to 70s for many.

&&

.DISCUSSION...
Issued at 258 PM CDT Wed Oct 8 2025

Tonight - Thursday Morning: Additional Frost Potential For West-
Central Wisconsin

GOES-19 water vapor imagery and 08.15z RAP 500mb heights depicts our
region currently being subjected to northwesterly flow with an upper-
level trough situated to our east and a ridge to our west. As a
result, we have a corresponding region of high pressure directly
overhead which has entrenched a cooler airmass in place. As we head
into the overnight hours, this surface high pressure system will
slowly push eastward allowing a relatively stronger pressure
gradient to sneak in west of the Mississippi River and increase our
surface winds slightly. Therefore, while the cooler airmass that has
resided in our region the last couple days remains in place, really
only expecting frost potential across portions of west/north-central
WI where winds will more likely remain light enough to contribute to
frost formation. Consequently, have issued a Frost Advisory for
these areas through 9am on Thursday.

Thursday - Friday: Showers Overnight Thursday

Thursday will feature the aforementioned surface high pressure
center pushing east of the local area allowing for slight moderation
in temperatures as the upper-level ridge further west tries to nudge
its way into the local area. However, its approach into the region
will be delayed as a shortwave that will cut-off into a closed low
pushes southeast out of Ontario and into the Great Lakes region. As
this occurs, a frontal boundary will push through the area with some
weak convergence out ahead. Consequently, noting fairly uniform
shower development within the CAMs during the late evening Thursday
through the overnight. This is seconded by the grand ensemble
(GEFS/EC/Canadian ensemble) which has very high (60-80%)
probabilities for measurable precipitation during this period.
As a result, have increased precipitation chances from the
national blend in accordance with these model trends.

This Weekend & Early Next Week: Trending Slightly Warmer, Occasional
Rain Chances

By the weekend the aforementioned upper-level ridge begins to slide
directly overhead allowing for a slightly warmer airmass to advect
into the region resulting in highs trending near to slightly above
normal. Sunday may feature the passage of a subtle shortwave that
may increase our precipitation chances for the second half of the
weekend. Consequently, noticing some fairly high probabilities for
measurable precipitation (50-80%) in the grand ensemble
(GEFS/EC/Canadian ensemble) during the Sunday into Monday period.

The pattern for next week begins to favor an upper-level trough
situating over the western CONUS with the upper-level ridge directly
overhead. As this trough very slowly tries to meander eastward,
shortwave perturbations will meander through the flow into the
Plains and Upper Midwest which may increase precipitation
chances throughout the week. However, the resolvability of any
particular shortwave at this time remains low. Regardless, would
expect temperatures to remain warmer than normal with
southwesterly flow into the area and at least some periodic
chances for precipitation into next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 627 PM CDT Wed Oct 8 2025

VFR conditions are expected through the period outside of
potential fog in the Wisconsin River valley around OVS tonight.
Winds, while light and occasionally variable overnight, will
tend to turn clockwise from out of the east- southeast to out of
the south-southeast with some gusts to 25 knots possible during
the day Thursday roughly along and west of a RGK-OLZ line,
including at RST.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory from 4 AM to 9 AM CDT Thursday for WIZ017-029-
     033-034-041>044-053-055.
MN...None.
IA...None.

&&

$$

DISCUSSION...Naylor
AVIATION...Ferguson