613
FXUS63 KARX 292012
AFDARX

Area Forecast Discussion
National Weather Service La Crosse WI
212 PM CST Sat Nov 29 2025

.KEY MESSAGES...

- Our long awaited winter storm has arrived, with light to
  moderate snow ongoing across the area through this evening.
  Winds will ramp up this evening as snowfall tapers off,
  leading to reduced visibility as blowing snow occurs. Near-
  blizzard conditions are likely (70% chance to drop below 1/2
  mile visibility) west of the Mississippi River valley.

- Cold temperatures remain through next week with highs in the
  upper teens to mid 20s. Overnight lows fall into the single
  digits above and below zero Monday morning and Thursday
  morning.

- Additional snow may (10-30%) occur Monday into Monday night,
  Wednesday, and Thursday night into Friday. Thursday night into
  Friday could presumably lead to impacts but details are far
  too murky to make any conclusions at this time.

&&

.DISCUSSION...
Issued at 209 PM CST Sat Nov 29 2025

Snow continues, looking ahead to blowing snow potential tonight

Light to moderate snow is ongoing across the CWA and a large swath
of the Midwest early this afternoon. Highest reports have occurred
to our south along Highway 20 roughly between Fort Dodge and
Hazelton where 8 to 12 inches of snow has fallen and continues. In
our neck of the woods, totals have generally been coming in on the
lower side of expected ranges with highest amounts in the south -
Oelwein had an estimated 8 inches as of noon - and lower amounts in
our north.

While totals have been a bit underwhelming thus far, given that we
expect the surface low to shift closer to our CWA and that lift will
be on the increase on the large scale as the main upper trough
approaches from the west and a zonal upper jet advances over IA,
have only adjusted event totals lower by 1-2 inches. Additionally,
forcing for ascent should be enhanced in our west by a 700/850mb
frontogenetic zone that is currently located over southern MN and is
leading to enhanced snowfall per latest surface obs, radar returns,
and webcam images.

Remaining questions surround potential for near-blizzard to blizzard
conditions this evening into tonight. As the surface low approaches
and deepens, northwesterly 40 knot 850mb jet sets up along and
west of a Rochester to Oelwein line while surface pressure rises
approach 1 mb/hr. Am highly confident (90%) gusts will reach
the 35-40mph range during the late evening into the nighttime
hours. Uncertainty surrounds how low visibility will drop. Per
29.12z HREF probs, wind gusts will begin to reach 35 mph closer
to 10pm while the 700/850mb frontogenetic zone discussed above
will begin to dissipate a few hours before that. Thus,
visibility reductions should focus on the ability for the winds
to loft fresh snowpack into the air. Consequently, thinking the
chance to reach a quarter mile or less is low (20%) with a very
small (10%) chance for visibility to remain around 1 mile or
greater during the overnight hours. Most probable outcome (70%)
is for visibility to hold around a half mile, enough for impacts
to continue overnight. Have therefore kept the Winter Storm
Warning going through the overnight hours even though new
snowfall should largely end after midnight. If the 700/850mb
band lingers longer than expected or these gusts generate lower
visibility by lofting snowpack than expected, would need to
explore a short fuse upgrade to a Blizzard Warning. Will thus
closely monitor obs, radar, and webcams in southern Minnesota
(status of the snow band) and the central third of Iowa (ability
for winds to loft snow as winds will increase in this region
first).

Cold week ahead

Persistent cyclonic flow centered over the eastern third of Canada
and the CONUS will lead to cold conditions for the next week.
Coldest mornings will occur after upper waves depart to the east
when surface ridging is maximized. Monday morning and Thursday
morning continue to appear to be the coldest in the 29.12z guidance
suite, when wind chills are favored to below zero across the area
and in the double digits below zero in parts of SW MN. Thursday
morning may see some values near -25, so will need to continue to
monitor this period over the coming days.

Additional shots at snow

Upper waves mentioned above will quickly translate over the central
CONUS Monday into Monday night, Wednesday, and again Thursday night
into Friday. At this time, pattern suggests some chance at impacts
with the Monday/Monday night wave and the Thursday night/Friday
wave. For Monday/Monday night, guidance has been fairly insistent
over several cycles that impactful snow will remain to our south.
For Thursday night into Friday, guidance has large spread with
regards to both timing and trajectory with an upper wave ejecting
northeastward from the Four Corners. At this time, NBM guidance
seems prudent across these time periods, but will need to watch
Thursday night into Friday closely over the coming days.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1140 AM CST Sat Nov 29 2025

Snow will continue through the overnight and gradually shift
east during the morning. Most of the snow is expected to be done
by mid to late Sunday morning. Predominant IFR to LIFR flight
categories, due to reduced visibilities from the snow and
lowered CIGS between 500 and 1500ft, through much of the TAF
period. As snow lets up Sunday morning, expect flight categories
to improve to MVFR as visibilities and CIGS increase. Northeast
winds this afternoon shift to northwest winds this evening and
continue through the TAF period. Northwest winds increase
overnight with gusts between 25 and 35 mph possible. With these
winds, localized blowing snow will be possible.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning until 6 AM CST Sunday for WIZ029-032>034-
     041>044-053>055-061.
     Winter Weather Advisory until 6 AM CST Sunday for WIZ017.
MN...Winter Storm Warning until 6 AM CST Sunday for MNZ079-086>088-
     094>096.
IA...Winter Storm Warning until 6 AM CST Sunday for IAZ008>011-018-
     019-029-030.

&&

$$

DISCUSSION...Ferguson
AVIATION...Cecava