469
FXUS63 KARX 091030
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
530 AM CDT Thu Oct 9 2025

.KEY MESSAGES...

- Passing band of showers and isolated thunderstorms moves
  through tonight, with overall minimal impacts expected.

- Dry to start the weekend with the threat for rain showers
  (40-60% chance) Sunday and Monday.

- Seasonal temperatures in the mid-60s to low 70s for the
  upcoming seven days--looking to turn cooler towards the end of
  next week.

&&

.DISCUSSION...
Issued at 305 AM CDT Thu Oct 9 2025

Showers and Isolated Storms Tonight:

Longwave ridging dominates the weather pattern over the central
CONUS early this morning and will continue to exert its
influence for the remainder of the week. A passing northern
stream vort lobe rippling along the U.S./Canadian border later
this evening and overnight will pull a tongue 320-325K
800-700-mb theta-e air north/east over the next 24 hours. This
ribbon of pre-frontal moisture will be the focus for scattered
elevated showers and isolated thunderstorms tonight before the
passage of the front brings an end to the rain threat by sunrise
Friday.

The 00Z HREF membership is in strong agreement that showers
will form within this moisture belt, but with the showers
battling poorer lapse rates and possibly even a cap around
700-600 mb, the coverage of the showers is somewhat in question.
Therefore, have withheld going higher than the NBM PoPs of
30-70%--highest north of I-90. No matter how you slice this
forecast, the impacts from the rain look minimal and transient.

Periodic Rounds of Rain Next Week:

Most of Friday and Saturday are looking dry with upper
tropospheric ridging and surface high pressure in control. A
longwave trough begins to impose itself on the upstream flank of
the ridge Saturday night with a sharp shortwave rounding the
base of the trough and lifting into the Northern High Plains
later on Sunday. A narrow warm sector lifts northward ahead of
the surface trough with modest mid-level 310K isentropic ascent
possibly fueling showers Sunday during the day before the
surface cold front plows ESE into the region Sunday night/Monday
morning, which could likewise serve as a focus for showers.

A lull in the rain is expected for Monday afternoon through
Tuesday as the overall pattern amplifies and the western CONUS
trough digs further into the Great Basin. The next perturbation
rippling off this longwave trough ejects into the north-central
CONUS for midweek and sets the stage for another round of rain.
The medium to longer range ensemble clusters are in good
agreement with the longwave pattern, but struggle with the exact
characteristics along the ridge/trough inflection point over
our region midweek. This makes is more tricky to pin down much
for timing details of the rain at this stage in the forecast.

Temperature Outlook into Next Week:

Overall, look for minimal fluctuation in temperatures for the
rest of this week into early next week. Highs oscillate around
or slightly above average for this time of year (low to mid-60s)
with lows in the 40s to low 50s, warmest ahead of the frontal
passages tonight and again Sunday night. A 5-10 degree spread
does creep into the temperature forecast by midweek owing to the
aforementioned ensemble spread along the longwave ridge/trough
inflection point. By next weekend into the following week (Oct
19-24), there is a appreciable cooling trend in the EPS/GEFS
with a number of members showing highs in the 50s or even the
upper 40s. Fall weather is certainly here to stay!

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 530 AM CDT Thu Oct 9 2025

Through 10.00Z, VFR conditions are forecast. Between 10.00Z and
10.12z, a band of showers and isolated thunderstorms will move
through the region. While ceilings will be primarily VFR, there
could be areas of MVFR/IFR visibilities mainly north of I-90.

Light sustained southeast winds will increase to 10 into 15
knot range and gusts will increase into the 15 to 25 knot range
this afternoon. LLWS is also a possibility as these showers
pass through at the end of the TAF period.


&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory until 9 AM CDT this morning for WIZ017-029-033-
     034-041>044-053-055.
MN...None.
IA...None.

&&

$$

DISCUSSION...Skow
AVIATION...Boyne