FXUS63 KARX 190612
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
112 AM CDT Tue May 19 2026

.KEY MESSAGES...

- The severe weather threat looks lower for tonight. As a
  result, the Storm Prediction Center has shifted the Slight
  Risk further south. The northern extent of the Slight Risk now
  only extends north to Interstate 90 where before it extended
  as far north as northeast Minnesota. 

- Patchy to areas of frost possible in north-central and central
  Wisconsin on Tuesday night and Wednesday night.

&&

.DISCUSSION...
Issued at 120 PM CDT Mon May 18 2026

This Afternoon and Tonight

The squall line that moved through our area last night has moved 
south into the Interstate 70 corridor. South of this line, the 
temperatures are in the lower 80s and dew points ranging from 
the mid-60s to lower 70s. With rain cooled air north of this 
boundary, this air mass will remain south of our forecast area 
for tonight. As a result, we have seen a reduction in the 
instability available for the storms along the cold front 
tonight. Surface-based CAPES which looked to be in the 1500 to 
2500 J/kg range yesterday are now only up to 750 J/kg. In 
addition, the stronger 0-3 km and 0-6 km shear remains post 
frontal. The CAMs are progressively moving the squall line 
further and further south. Much of the consensus in the CAMs has
this squall line moving east across southern Iowa and northern 
Missouri. Further north, there are more scattered thunderstorms.
This has reduced the severe weather threat because there would 
be less coalescing of the cold pools. 

Due to this, we reached out to the Storm Prediction Center and 
was able to get a more southern shift in the Day 1 Slight Risk. 
It is now south of Interstate 90. There is now a Marginal Risk 
from Interstate 90 north into Upper Michigan. If there is severe
weather, it would occur between 19.03z and 19.07z. The primary 
threat would be damaging winds.

Tuesday

A northern stream shortwave trough will move northeast across 
western and northern Minnesota and northern Wisconsin. This will 
result in some scattered morning showers. The strong cold air 
advection in the wake of the cold front will continue into the 
day. High temperatures for the day will occur around midnight in
the mid- and upper 60s. Temperatures during the day will be in 
the 50s and 60s.

Tuesday Night and Wednesday night

The combination of mostly clear to partly cloudy skies and light 
winds will allow temperatures to fall into the 30s and 40s. There 
could be the potential for even colder temperatures in central and 
north-central Wisconsin. This could result in some patchy to 
areas of frost in our traditional cooler areas of central and 
north- central Wisconsin.

Friday into the Weekend

A northern stream shortwave will move slowly east through the 
region. As this occurs, there will be periodic showers and storms. 
Like yesterday, both the 0-3 and 0-6 km shear remain less than 
30 knots. As a result, the probabilities for organized severe 
weather look low.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 103 AM CDT Tue May 19 2026

Strong winds in the wake of exiting precipitation will shift
east, gusting 40kt at KLSE at 19.06Z TAF issuance. MVFR-IFR
ceilings seen over central Minnesota shift southeast into the
area overnight, affecting both KLSE and KRST TAF sites.

Aviation impacts lift through Tuesday morning and afternoon 
with scattered showers and strong northwest winds. 

&&

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

&&

$$

DISCUSSION...Boyne
AVIATION...JAR