469
FXUS63 KARX 121816
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
115 PM CDT Sun Oct 12 2025

.KEY MESSAGES...

- Scattered to widespread showers tonight (50-80%) - highest
likelihood north of I-90. Low end QPF for most (1/10 to 1/4").

- Periodic rain chances then for the latter half of the week.

- Mostly at/above normal temps through the new week. Coolest days
Tue/Wed.

&&

.DISCUSSION...
Issued at 115 PM CDT Sun Oct 12 2025

GEFS and EPS remain in good agreement with keeping the upper level
flow rather progressive, moving shortwave troughs/ridges west to
east across the CONUS - influencing the upper mississippi river
valley for about 2 days before swapping out trough for ridge,
ridge for trough, etc. The pattern favors periodic rain chances
along with temps at/above the seasonable normals (but with a fair
amount of variance).


> RAIN CHANCES: band of north-south running showers across
MN/northern IA continue to lift northeast at early afternoon -
relating to a weak upper level shortwave and mid level Fgen. While
deeper saturation is aiding the pcpn along the northern portions of
showers, the southern fetch is falling out of a mid deck, having to
work through a dry sub cloud layer. With the deeper lift continuing
on the northeast tack the CAMS suggest the southern extent will
decrease aerially and in intensity. Reasonable in this set up.
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1230 AM CDT Sun
Oct 12 2025

Increasing south-southeast winds early this morning ahead of a
frontal boundary will be initial aviation impact for the 12.06Z TAF
period. Higher dewpoint temperatures on surface observations
concurrent with meager radar returns places the north-south oriented
frontal boundary upstream through central Minnesota at 12.06Z TAF
issuance. Increased winds of 25+kt gusts ween within this warm
sector. While accompanying precipitation cannot be ruled out through
much of today with the increasing moisture advection, overall lower
confidence (<30%) and coverage keeps mention out of either TAF site
at current forecast hour.

Higher precipitation chances progress from west to east later this
evening, becoming more widespread locally overnight into early
Monday morning. Northern jaunt to deepening surface low into
southern Canada limits initial confidence locally to north of
Interstate 90 until frontal boundary passage, near or shortly after
terminus of 12.06Z TAF issuance. Therefore, haven`t increased
precipitation mention at either TAF site at this time and will need
to be further assessed in coming TAF issuances. MVFR ceilings and
visibilities will be main impacts accompanying precipitation.

MONDAY THROUGH WEDNESDAY... Precipitation chances and any
accompanying aviation impacts wane through Monday morning.
Subsequent potential precipitation (20-50%) and aviation impacts
Tuesday through Wednesday.

Moving into late afternoon/early evening and then for the rest of
the night the same CAMS suggest a few bands of showers will develop,
responding to low level moisture transport and sloping Fgen. Another
shortwave trough will add to the mix, but likely only influences
northern reaches of the region as it spins over northern MN into
southern Canada. Low level saturation on the increase starting this
evening. So while the preponderance of the lift will be related to the
front, it will have saturation to work with. PWs push 1 1/2" with
NAEFS PW anomalies +2 to +3. That said, the lift isn`t strong, nor
necessarily deep, and QPF in short term models hold rainfall in
check as a result. The HREF paints 40-60% for greater than 1/10"
north of I-94 with only 20-30% chances to exceed 1/4". QPF less
south of I-90. CAMS continue to suggest a very cellular nature to
the pcpn (much like current radar trends), so locally higher amounts
could be realized if a location receives a few rounds from perkier
showers. Little if any instability and thunder threat looks low to
none as a result.

After tonight more light rain chances could work into the area Tue
as weak ripples in the upper level try to work under developing
ridging. A consistent signal in the models although how widespread
resulting chances would be is in question. Not much for moisture
return/transport with the more favorable, moist airmass holding
south/west. QPF isn`t much locally as a result with 25-50% to exceed
1/10" per the LREF.

Again, progressive (aka, active) weather pattern through the weekend
with more rain chances. These are more likely to be tied to
stronger, synoptic scale systems - with broader areal coverage and
more QPF. Will hold with the model blend for the details.


> TEMPERATURES: cold front pushes east across the local area Monday
morning with 850 mb temps set to fall from as warm as 14 C at 12z
Mon to 5 C by 12z Wed. Highs Tue/Wed shaping up to be the coolest of
the week as a result with LREF probabilities suggesting 10 to 50%
chances to warm above 60. All in all though, that still sits close
to the mid Oct normals. Temps then rebound as upper level ridging
becomes the main weather influence. At least 50% of the GEFS and EPS
members paint mid 60s to around 70 for highs Thu into Sat. High end
outliers (upper 5%) hint that some low 70s could be reached for a
few locations. No widespread frosts through the new week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1230 PM CDT Sun Oct 12 2025

Confidence in a period of showers this evening is increasing as a
front slides eastward through the region. A few observations
reporting light rain over south-central MN this afternoon, but much
of the activity currently on radar is evaporating in a dry layer
near the surface. Increasing moisture in the vicinity of the front
will provide a favorable 2-4 hour window for showers after 00Z this
evening, with small chances (30%) lingering for a time behind the
initial rain band. Most of the activity should exit RST/LSE by 07-
08Z.

Breezy south-southeast winds this afternoon will gust to 20-30
knots, mainly at RST, before weakening a bit with the frontal
passage this evening. Lingering gustiness at RST should mitigate
LLWS concerns there, but marginal LLWS is possible for a few hours
this evening at LSE if surface gustiness would subside there. Have
left out of TAF for now given low confidence.

Ceilings will decline overnight behind the front but should stay
VFR. Clearing into Monday morning with winds shifting to northwest.

&&

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

&&

$$

DISCUSSION...Rieck
AVIATION.....Kurz