Ontario Wisconsin Weather Forecast Discussion

927
FXUS63 KARX 092358
AFDARX
Area Forecast Discussion
National Weather Service La Crosse WI
658 PM CDT Thu Oct 9 2025
.KEY MESSAGES...
- A line of scattered showers/storms is expected tonight through
  Friday morning (30-70%). Impacts are expected to be minimal
  with rainfall amounts under 0.25 inches.
- A mostly dry weekend is expected ahead of shower potential
  again Sunday into Monday (20-50%).
- Seasonable temperatures are expected over the next 7 days with
  highs in the low to mid 60s and lows in the 40s to low 50s.
&&
.DISCUSSION...
Issued at 205 PM CDT Thu Oct 9 2025
Showers and Storms Tonight Through Friday Morning
Upper level longwave ridging remains the primary influence of
our weather today through the weekend. A transient 500hPa wave
sinks southward into the Great Lakes region along the United
States/Canada border forcing a frontal boundary east-southeast
through the Upper Midwest tonight into Friday. 850hPa moisture
transport along the front combined with forcing from the
boundary itself is expected to spark a line of scattered showers
and isolated thunderstorms along said boundary as it moves
through the region (30-70%). Given the progressive nature of the
wave/associated surface boundary, overall impacts are expected
to be minimal. Rainfall amounts at any given location are
expected to be generally 0.1-0.25 inches as suggested by the
09.00z HREF LPMM although a few pockets of locally higher
amounts are possible, primarily north of I-90. Showers and
storms move east of our area by mid morning Friday with breezier
conditions come the afternoon.
Mostly Dry Weekend Before Additional Shower Potential
Ridging takes hold over the region again behind the
aforementioned wave and showers tonight into Friday which will
continue to influence our weather through Sunday. As such, dry
conditions are anticipated under the associated height rises and
subsidence.
On Sunday, another 500hPa shortwave ejects into the Northern
Plains, promoting surface cyclogenesis, which will be the focus
of additional precipitation chances. In response to the
developing surface low to our west, 850hPa warm air advects into
the region during the day Sunday, which could promote some
shower development during the daytime hours with 20-40%
probabilities depicted in the 09.13z NBM. Then, the associated
cold front moves eastward through the Upper Midwest Sunday
evening into the overnight hours, becoming another catalyst for
shower and perhaps isolated thunderstorm development (30-50%).
Drier conditions then develop for the beginning of next week as
ridging and high pressure again build across the central United
States.
Seasonable Temperatures Through the New Week
Temperatures remain fairly consistent over the next 7 days. The
various shortwaves followed by ridging/high pressure indicates
airmasses are not able to stagnate for long. As such,
temperatures right around normal are expected with high
temperatures generally in the low to mid 60s and low
temperatures in the 40s to low 50s. Increased spread in the
ensemble guidance develops by the middle of next week, leading
to uncertainty in the ultimate temperatures.
&&
.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 658 PM CDT Thu Oct 9 2025
Showers and isolated storms will be the primary TAF concern through
the overnight as a frontal passage will bring a broken line of
showers and embedded storms through the area. MVFR to IFR vsby
reductions will be possible underneath any showers and storms. As
the front moves eastward, showers and storms will exit the local
area around daybreak. LLWS will be present with an increasing
low-level jet with the frontal passage as the recent RAP
soundings having winds in the 1-2kft layer of around 30-40 kts.
Otherwise, conditions will improve to VFR with minimal sky cover
for the afternoon on Friday. Winds will begin from the south at
around 10-15 kts but will shift to northwesterly after the
front passes through during the middle and later morning hours
with occasional gusts of 20-25 kts possible, primarily in
unsheltered areas of southeast MN and northeast IA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
DISCUSSION...Falkinham
AVIATION...Naylor

NWS ARX Office Area Forecast Discussion