Monona, Iowa Weather Forecast Discussion

699
FXUS63 KARX 052338
AFDARX
Area Forecast Discussion
National Weather Service La Crosse WI
638 PM CDT Sun Oct 5 2025
.KEY MESSAGES...
- FINALLY! Showers, a storm or two this evening, lingering rain
chances into Monday (mostly south of I-90).
- Much cooler, albeit seasonable start to the new work week (20
degrees colder compared to today). Gradual warming for mid week
into the weekend.
&&
.DISCUSSION...
Issued at 130 PM CDT Sun Oct 5 2025
* TONIGHT THROUGH TUESDAY: showers, perhaps a storm or two,
  tonight into Monday. Cooler, albeit more in line with the
  seasonable norms.
> RAIN CHANCES: a smattering of mid level showers in a region of
moisture transport ahead of a sfc cold front continues northeast-
southwest over MN early this afternoon - tracking east. Expectation
is for this activity to become more widespread in coverage moving
into the late afternoon/early evening hours as low level sfc
inversion is overcome and weak instability develops. MUCAPES are
only progged around 500 J/kg in the RAP and profiles are "skinny" at
best. Likely more showers with an isolated storm here and there.
Weakening with a decrease in areal coverage as we move into the
later night time hours (loss of instability).
Moving into Monday the cold front lays out from southeast WI
southwest across easter IA at 18z. Bits of shortwave energy progged
to roll across the boundary - and showers/a few storms should
continue to spark in the vicinity of the front as a result. The
instability, limited as it is, will likely hold south of the local
forecast area - keeping thunder chances south.
> TEMPERATURES: Much cooler, albeit more seasonable, air flows in
post the cold front. 850 mb temps progged to fall from around 15 C
this afternoon to 5 C by Tue morning. The HREF holds highs at 65
degrees or cooler Monday (100% chances for this). A few degrees
warmer Tue. With clear skies and light winds expected Tue night,
some threat for frost development from the I-94 corridor northward.
* WEDNESDAY INTO THE WEEKEND: gradual warming, trending dry for most
  days
GEFS/EPS in solid agreement with building longwave ridging across
the central U.S. by the middle part of the new week. A shortwave
trough is progged to drop southeast out of Canada Thu, skimming
across the northern great lakes as it cuts across the ridge axis.
Some amplification of the ridge post the trough - with the ridge set
to work over the upper mississippi for the weekend. All WPC clusters
in agreement with this now - previous runs suggested the potential
for another trough to track across the region, a solution some of
the GEFS members favored. Not shaping up to be a blocking pattern
(ala the past week) as the GEFS and EPS focus on a more progressive
flow sliding into the following week.
> TEMPERATURES: after a the dramatic drop in temps from today to
Monday (20 degree fall in highs), the upper level pattern and a
return of more southerly flow suggest a gradual warm up from mid
week through the weekend. Upper 75% of the GEFS and EPS members warm
highs in the mid-upper 70s for the weekend with a few members
pushing 80 degrees for some locations.
> RAIN CHANCES: a piece of the upper level energy with the mid week
shortwave could slip across the region late Thu night/Fri morning
bringing some rain chances. Not clear on where this perturbation
would move and saturation could be a limiting factor. NBM paints low
end rain chances (20-30%) Thu/Thu night which looks reasonable for
now.
After that, the next rain chances could hold off until the end of
the weekend as the ridge axis becomes the main weather influence.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 619 PM CDT Sun Oct 5 2025
An ongoing southwest to northeast oriented line of rain showers
with isolated embedded at 06.00Z TAF issuance is seen
bifurcating the forecast area from northeast Iowa, through
southeast Minnesota, and into central Wisconsin on radar
imagery. A meager southeast trajectory of this line is expected
to cause impacts area wide overnight into early Monday morning.
Other that isolated thunder, transient MVFR visibilities have
been realized within the heavier rainfall rates. IFR ceilings
expected within this line early Monday morning primarily from
northeast Iowa into southwest Wisconsin. Current confidence
places these impacts south of both TAF sites but will require
further monitoring and amendment in coming TAFs.
MONDAY NIGHT THROUGH WEDNESDAY... Lingering IFR ceilings
possible locally from far southwest Wisconsin into northeast
Iowa Monday night. Mostly VFR expected through midweek with
limited fog probabilities in central Wisconsin.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Rieck
AVIATION...JAR

NWS ARX Office Area Forecast Discussion