FXUS63 KARX 200509
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
1209 AM CDT Wed May 20 2026

.KEY MESSAGES...

- Staying cool and mostly dry until Friday with increasing rain
  chances. 

- Warmer this weekend into early next week.

&&

.DISCUSSION...
Issued at 1206 AM CDT Wed May 20 2026

Today - Thursday: Dry with Below Normal Temperatures 

An overall benign pattern expected for the next 2 days with dry 
conditions set to triumph. Surface high pressure, currently over the 
Central Plains, will shift east through the day tomorrow, sliding 
into the Great Lakes region by early Thursday. As the high moves 
through tomorrow, light northerly winds will prevail with plenty of 
sunshine to start the day before high clouds overspread the area 
from the east/southeast. Temperatures both tomorrow and Thursday 
will be below normal in the lower 60s. Unlike some of our previous 
post-frontal-passage, northwesterly-surface-flow events, the airmass 
moving in amidst the cold air advection is not as dry with dew 
points only falling into the mid 30s. This will help to prevent 
overnight lows from dropping too close to freezing to warrant any 
frost/freeze headlines. 

Friday - Sunday: Warming With Some Rain Chances 

Chances for rain look to return overnight into the morning on 
Friday. As a developing trough across the Northern US Rockies starts 
to deepen, southwest flow will begin to take shape over the Upper 
Midwest late Thursday. With the surface high pressure finally moving 
off to the east, this will help to mitigate some of the dry air in 
the lower levels. Deeper mid-level moisture will be pulled into the 
region and will interact with the passing shortwave trough through 
the day on Friday. With little to nothing in the way of surface 
forcing, PoPs remain pretty broad-brushed overall with widespread 30-
60 percents across the region for much of the day.

As the upper trough pivots to the north and east into Western 
Ontario over the weekend, lingering shortwave energy and deep 
moisture will allow for continued low rain chances, even though 
forcing overall looks much more nebulous than Friday. Given the 
uncertainty in the location of best forcing, will continue with the 
blended guidance that generally caps PoPs at 25 percent after 
Saturday morning. 

Early Next Week: Much Warmer 

Temperatures from Friday onwards will be on an upward trend but 
should peak early next week as a fairly significant upper ridge 
builds across the Central CONUS in the wake of the departing 
shortwave trough. A dome of anomalously warm 850 mb temperatures (5-
15 degrees C above normal) over the Northern Plains will start to 
seep eastward into the Upper Midwest by Monday and continue into mid-
next week. Combined with warm air advection from southerly surface 
flow, temperatures will be well above normal by Monday with highs in 
the low to mid 80s.  This significant warm up is expected to continue 
through at least mid-week. 

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1206 AM CDT Wed May 20 2026

VFR expected through the 20.06Z TAF period. A VFR stratus deck
will linger in central Wisconsin through the morning hours,
potentially grazing KLSE TAF site with FEW. Light winds
gradually turn clockwise through the period.

Next widespread aviation impacts expected Friday. 

&&

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

&&

$$

DISCUSSION...Barendse
AVIATION...JAR