100
FXUS63 KARX 301725
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1225 PM CDT Wed Sep 30 2026

.KEY MESSAGES...

- Heavy rain tonight and Thursday morning in Fayette and Clayton
  counties in northeast Iowa, and Grant County in southwest
  Wisconsin. The far southern portions of these counties may see
  2 to 4 inches with localized higher totals.

- Central and north-central Wisconsin may see patchy to areas of
  frost on Friday night and areas to widespread frost on Sunday
  and Monday nights.

&&

.DISCUSSION...
Issued at 1205 PM CDT Wed Sep 30 2026

Tonight and Thursday

The remnants from Hurricane Polo will move northeast through Iowa,
northern Illinois, and the southern third of Wisconsin tonight.
Precipitable water values late tonight will quickly climb and range
from 2 to 2.25 inches across southern and eastern Iowa, northern
Illinois and far southern Wisconsin. Precipitable water values will
be around 1.5 inches in La Crosse, and around 1 inch near Black
River Falls. The heaviest rain will likely fall from Omaha, NE
to Dubuque, IA to Grand Rapids, MI. Mean rainfall totals will
likely range from 2 to 5 inches. The 24-hour QPF ensemble
localized probability-matched means are as high as 7 inches.
These may impact far southern Fayette and Clayton counties in
northeast Iowa and Grant County in southwest Wisconsin. Rainfall
totals quickly decline as you move northeast toward to La
Crosse where rainfall totals will likely range from a quarter-
to half-inch and only up to a tenth of an inch near Interstate
94. As the surface wave moves quickly away from the area on
Thursday morning, the precipitable water values will quickly
drop and the rain will move out of the area. Most areas should
have a dry afternoon.

Low temperatures tonight will range from the mid-50s to mid-60s.
High temperatures on Thursday will be in the mid- to upper 60s.

Thursday Night into Friday Night

High pressure will provide dry weather. High temperatures will range
from the upper 50s to mid-60s on Friday. Low temperatures will range
from the upper 30s to upper 40s on Thursday night, and from the mid-
30s to mid-40s on Friday night. The temperatures will be cold enough
on Friday night that there could be some areas of frost in central
and north-central Wisconsin.

Saturday and Saturday Night

A cold front will move southeast through the area from late Saturday
afternoon into Saturday evening. This front could produce some
scattered light rain showers as it moves southeast through the Upper
Mississippi River Valley. High temperatures will be in the mid-60s
on Saturday, and low temperatures will range from the mid-40s to
lower 50s.

Sunday through Tuesday Night

High pressure will provide dry weather. High temperatures will range
from the upper 50s to mid-60s. Low temperatures will range from the
lower 30s to mid-40s on Sunday and Monday nights. The temperatures
will be cold enough for areas to widespread frost in central and
north-central Wisconsin. Low temperatures will range from the mid-
40s to mid-50s on Tuesday night.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1220 PM CDT Wed Sep 30 2026

Low ceilings and fog did indeed work into RST/LSE this morning
and unfortunately for VFR fliers, reductions are expected for
the next 24 hours. Some locations, particularly northwest of a
CCY-LSE-BKC line, will see a brief interlude of MVFR this
morning before IFR ceilings return overnight. Increase in
moisture will lead to rain in far SW WI and NE IA and should
also cause fog to develop as well. Needless to day, IFR is a
very good bet (80%) at RST/LSE before a shift to winds out of
the north brings drier air and improvement near the tail end of
the period or during the 18z-21z Thursday time frame.

&&

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

&&

$$

DISCUSSION...Boyne
AVIATION...Ferguson