718
FXUS63 KARX 060724
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
224 AM CDT Sun Sep 6 2026

.KEY MESSAGES...

- Very low chances (<15%) for rain showers across Southeast Minnesota
  and Northeast Iowa today. Better chances to stay west of the
  I-35 corridor.

- Chances for showers/storms return in earnest (60-90%) for
  Tuesday with heavy rain being the main concern.

- Dry conditions and near normal temperatures to prevail from
  Wednesday through the end of the work week.

&&

.DISCUSSION...
Issued at 221 AM CDT Sun Sep 6 2026

Morning Fog & Storm Chances Staying West Today:

It`ll be a foggy start to the day with light winds and stout surface
moisture allowing for widespread patchy fog development across the
region. To our west, across Western and Central Minnesota, showers
and thunderstorms are expected to develop late tonight into the
morning hours along the leading edge of some theta-e advection.
Additional convection is expected to develop through the afternoon
along an axis of instability just to our west. A stout layer of warm
and dry air in the low levels across our area around 850 mb should
keep areas east of the I-35 corridor capped enough to limit any
convective development making its way into our area.

Increasing Rain Chances Through Start Of New Week:

By Monday, an upper wave will begin to eject out of the Pacific
Northwest and into the Northern High Plains. At the surface, a low
pressure center is expected to move out of the Northern Rockies and
into the Canadian Plains, gradually occluding into midweek. As the
upper level trough axis moves into the region, it will encroach on a
very moist warm sector and provide some additional support aloft,
setting off convection. 05.18Z ensemble soundings do not show a
particularly unstable environment across our area with a strong cap
in the low levels noted but pWats could very likely be in the 1.75-
2+ inch range so heavy rainfall along and ahead of the frontal
boundary will be something to keep an eye on. Storm motion and
overall boundary movement look to be progressive enough to limit any
significant flash flooding concerns but 0.5-1 inch totals over a 6-
12 hour period are not out of the realm of possibilities. The
heaviest rain should occur through the day on Tuesday with chances
decreasing through the overnight hours as moisture gets scoured out
by the frontal boundary early Wednesday morning.

Wednesday - Next Weekend: Drying Out, Near Normal Temperatures

As the upper wave/trough axis move east, the trailing frontal
boundary from the occluding surface low well to our north in Canada
will sweep through the region. This will finally usher in a drier
airmass to the region as a whole with dew points falling back into
the upper 50s. A weak surface high is expected to build into the
Midwest by Thursday. This, in combination with zonal flow to weak
ridging aloft, will keep conditions dry for the late week period.
Temperatures behind the front won`t be much "cooler" but they will
be a bit closer to normal in the 70s to lower 80s Thursday and
Friday. The next chances for rain look to come by the weekend as
another upper wave looks to potentially swing through the upper
Midwest.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1233 AM CDT Sun Sep 6 2026

Main aviation impacts expected in the near term with FG
potential already seen initiating east of the Mississippi River
Valley with IFR-MVFR visibilities. Given the reduction in
observations at 06.06Z TAF issuance, have brought LIFR FG to
KLSE through the overnight hours. Lesser confidence west of the
Mississippi River Valley where model guidance wants to bring
reductions while mid to upper level clouds are limiting surface
cooling potential. Have continued with previous forecast based
on previous nights impacts and model guidance but will require
additional amendment as sky cover clears or impacts come to
fruition. Expect impacts to lift through the morning hours.
Additional fog impacts possible overnight into early Monday
morning.

&&

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

&&

$$

DISCUSSION...Barendse
AVIATION...JAR