181
FXUS63 KARX 131837
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
137 PM CDT Sun Jul 13 2025

.KEY MESSAGES...

- Smokey skies clear out by Monday with very low (10%)
  probabilities for showers tonight into Monday.

- Next chance of widespread showers and storms comes Tuesday
  night through Wednesday. The severe weather potential looks
  low at this time.

- Cooler for the end of next week with highs in the 70s from
  Thursday into the weekend.

&&

.DISCUSSION...
Issued at 135 PM CDT Sun Jul 13 2025

This Weekend into Early Next Week: Smoke Departs, Mostly Dry

With increasing southwesterly lower tropospheric flow advecting
our overnight smoke to the northeast, visibilities have
steadily improved this morning and were in the 5-8 mile range by
noon. The smoke should continue to push out of the region
overnight. Decaying convection slides southeastward out of
central Minnesota tonight along a weakly confluent near-surface
boundary. While forcing is not strong, the moisture axis narrow,
and mid-level lapse rates poor, there is just enough of a
window to support high-based showers to warrant adding in a
corridor of sprinkle wording to the forecast after 06Z and into
the early morning on Monday.

Increasing warm air advection during the day on Monday should
wash out/lift north whatever is left of this boundary during the
day. Muggy summertime air returns northward with this southerly
flow with highs reaching into the mid-80s to near 90. Cannot
fully rule out some afternoon convection along the retreating
boundary north of I-90, but details are too muddy to hang one`s
hat on.


Tue - Wed: Next Chance of Widespread Showers and Storms

Broad WSW flow gradually amplifies across the region between
Monday and Wednesday evening with an upstream trough across the
Rockies helping to usher a cold front southeastward out of the
Canadian Prairies. With the frontal orientation nearly parallel
to the upper level flow, convection that does initiate along it
will quickly grow upscale into a line and the overall severe
threat will be limited in space and time. The first round of
storms is progged to form over North Dakota and northwestern MN
Monday evening. How far south the cold pool from these storms
can advance against a modest 30-40-kts LLJ will dictate where
storms fire on Tuesday afternoon, most likely across central MN.
The LLJ will be weaker Tuesday night and allow the cold pool
from these storms to surge farther south, but storms will
definitely be in a decaying state if/when they reach the
forecast area.

For Wednesday, convective debris looks to linger, but how much
and where remains a wild card in the forecast. It is no surprise
then that there is a modest spread in the temperature forecast
for Wednesday, dictated by the degree of cloud cover and
showers. The front looks to clear the forecast area by the
evening as the surface low passes through.


Late Week: Cooler, Drier

The end of the week will be characterized by a period of cooler
weather more typical of mid-September as a shot of polar air
grazes the region. The chances of precipitation during this
window are fairly low (< 20%) and would be towards the Highway
18 corridor and on south. Overnight lows will be driven by the
degree of cloud cover and could fall into the mid to upper 40s
(the NBM 10th percentile) in favored spots east of the
Mississippi if conditions align perfectly. By the weekend, the
progressive zonal flow undulates again and warm air advection
ensues.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1231 PM CDT Sun Jul 13 2025

VFR expected though the period. Overnight and early morning /09-15Z/,
a very low chance of showers or possibly TSRA (10%) occurs with
a weak trough moving through from west to east, along with some
instability along it. For now have handled it with a SCT060 as
confidence is low for this to materialize, especially to
affect the KRST/KLSE airfields.

&&

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

&&

$$

DISCUSSION...Skow
AVIATION...Baumgardt