FXUS63 KARX 161038
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
538 AM CDT Thu Apr 16 2026

.KEY MESSAGES...

- The risk for severe storms across the region is increasing for
  Friday afternoon with all hazards possible. The main
  uncertainty in the forecast revolves around when the storms
  form, which will dictate what areas see a certain threat.
  Continue monitoring forecast for further details.

- Near to below freezing overnight low temperatures through the
  weekend. A few snow flurries cannot be ruled out on Saturday,
  mainly along and northeast of I-94.

&&

.DISCUSSION...
Issued at 1159 PM CDT Wed Apr 15 2026

Dry Today:

A reprieve in storm chances today from passing anticyclonic flow
ushering in a drier airmass will feel less humid compared to
previous days with surface dewpoint temperatures in the 40s to low
50s. The break in precipitation also allows over saturated
soils to recover some from heavy, high rainfall amounts over the
last few days. Fire weather concerns expected to remain
northwest of the local forecast area into central Minnesota.

Severe Storms Likely Friday:

A stout longwave upper level trough seen progressing east over the
Pacific Northwest on GOES water vapor loops excites low level
moisture transport through the Central to Northern Plains
Thursday, progressing through the Upper Mississippi River Valley
Friday. Accompanying instability of 2000+ J/kg MUCAPE seen in
low and high resolution models builds through the forecast area
before eventual fropa Friday night. While LREF dProg/dt remains
mostly consistent, a slightly more phased solution to the low
has increased intraensemble agreement for a deeper low pressure
center slightly farther north from west-central into northern
Wisconsin. The concurrent steep mid level lapse rates (GFS
15.18Z) of 9.5C+/km raise initial supercell concerns through
Friday afternoon as a meso low phases/occludes along our
western/northern periphery.

Therefore, model derived significant severe parameters
illuminate initial stronger severe threats during supercellular
storm mode Friday afternoon through some of the forecast area
before fropa causes linear storm mode to progress from northwest
to southeast through the evening into the nighttime hours. All
storm modes remain possible with highest potentially strong
tornado threat during the afternoon should surface based
supercells form along a lifting boundary. Tornadoes within
linear storm mode later through Friday remain possible albeit
potentially not as strong. Very large hail and damaging winds
will be possible with all storm modes.

Winter Resemblant Weekend Expected:

A colder airmass settles in through the weekend, ushering in winter
precipitation chances Saturday into Saturday night. Deepening
on growing season, confidence in near to below freezing
overnight low surface temperatures may require subsequent Frost
Advisory or Freeze Warning issuance Friday, Saturday, and Sunday
nights. Unfortunately, low (<15%) LREF joint probabilities for
shear and CAPE graze the local forecast area again by the middle
of next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 535 AM CDT Thu Apr 16 2026

A narrow band of IFR to LIFR fog and low stratus east of a CCY
to MDZ line steadily clears by mid-morning with VFR conditions
for the rest of the TAF period. Light northwest winds this
morning back to the south and increase through the late
afternoon and overnight, gusting to 15-25 kts west of the
Mississippi River by sunrise Friday. Lower elevation TAF sites
may see LLWS for a time tonight, but this appears to be
marginal at this time and will be monitored through the day.

&&

.HYDROLOGY...
Issued at 535 AM CDT Thu Apr 16 2026

Dry conditions today provide a temporary reprieve for saturated
soils and localized flooding. Crests for ongoing rivers in flood
across Wisconsin will work downstream into early next week.
Unfortunately, heavy rain potential increases Friday afternoon
as a line of storms progresses from west to east. The heaviest
rainfall amounts of 1-2 inches are likely to fall in narrow
corridors, but will be dependent on how quickly storms grow into
a line versus remaining isolated. The highest confidence in
higher rain amounts will be east of the Mississippi where rivers
will still be in flood. Continue monitoring upcoming forecasts
for the location of highest QPF amounts.

&&

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

&&

$$

DISCUSSION...JAR
AVIATION...Skow
HYDROLOGY...Skow