207
FXUS63 KARX 301833
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
133 PM CDT Sat Aug 30 2025

.KEY MESSAGES...

- Mostly dry conditions this weekend with an isolated shower or
  storm possible for portions of southeast Minnesota and
  northeast Iowa, with the better chances remaining west of
  I-35.

- The chances for widespread rain continue to increase (50 to
  70%) for Tuesday into Wednesday as a cold front moves through
  the region.

- Near-normal temperatures through Tuesday then below normal
  temperatures through the end of the week.


&&

.DISCUSSION...
Issued at 131 PM CDT Sat Aug 30 2025

Today-Monday: Mostly Dry and Seasonable Temperatures

The surface boundary that has been over the region the past couple
of days has shifted into central Iowa. There is still a little
uncertainty with how far south it goes, so a shower or storm can not
be ruled out for portions of northeast Iowa this afternoon and
Sunday afternoon. By Monday, the boundary shifts back a little
northeastward and thus increases PoPs a little (10 to 20%) for
portions of northeast Iowa and southeast Minnesota with the better
chances staying west of I-35. With surface high pressure over the
area through Sunday, fog will be possible especially in low lying
areas and river valleys. Seasonable temperatures in the mid to upper
70s are expected into early next week.

Tuesday-The Weekend: Trending Cooler with Rain Chances Midweek

Heading into Tuesday, a strong trough and associated cold front digs
down into the Upper Midwest and Great Lakes Regions. With the
current timing, the cold front arrives late Tuesday into early
Wednesday morning. This will bring increased chances of showers and
storms (50 to 70%) for Tuesday evening through Wednesday morning.
PWATs are around the 0.8 to 1.25 inch range so the rain totals will
be relatively light, as is depicted in the 00Z LREF where there is a
30 to 60% chance for at least 0.25 inches to fall, with the higher
probabilities in central Wisconsin. With cyclonic flow in place as
the trough gradually shifts eastward, rain showers may be possible
both Thursday and Friday.

The bigger impact from this deep trough moving into our region will
be the cooler temperatures. The 850mb temperatures for Thursday
range from 1C to -3C. There are some differences in the ensemble and
deterministic guidance as the GFS and GEFS seems to be a bit cooler
than the ECMWF and EPS, however the confidence for temperatures to
be quite a bit below normal are high. EFI values for Thursday
continue to range from -0.8 to -0.9 which indicate the high and low
temperatures for Thursday are on the lower end of climatological
normal. Current NBM populates Thursday morning with lows in the mid
30s in Central Wisconsin to the low 40s for everywhere else in our
CWA. High temperatures for Thursday are now forecasted to be in the
mid to upper 50s. Now these temperatures will continue to fluctuate
a bit as we are still 5 days away from this taking place. After
Thursday, temperatures gradually warmup as the trough shifts
eastward and by Saturday we are looking at temperatures back near
70F.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1240 PM CDT Sat Aug 30 2025

MVFR to IFR cigs persist across portions of southeast MN this
afternoon with KRST still observing 600 ft cigs as of 17z. This is
expected to continue to improve over the next couple of hours to
eventually VFR conditions. However, as we head into the overnight
hours, the nocturnal inversion coupled with light sfc winds will aid
in additional fog and low-stratus development across portions of
the local area. As a result, have included some MVFR to IFR
reductions at both KLSE and KRST with the potential for further
reductions to LIFR possible. Eventually, as daybreak comes on
Sunday, any low-stratus and fog will quickly mix out leaving
VFR conditions in place. Winds will being the period from the
east around 5 kts before becoming light and shifting southeast
overnight.

&&

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

&&

$$

DISCUSSION...Cecava
AVIATION...Naylor