Chaska, Minnesota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

810
FXUS63 KMPX 220458
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1058 PM CST Sun Dec 21 2025

.KEY MESSAGES...

- Chance of wintry mix late this evening into Monday morning.
  Minor ice and snow accumulations are possible.

- Mild temperatures and weak disturbances with low predictability
  are in store over the next 7 days.

&&

.DISCUSSION...
Issued at 250 PM CST Sun Dec 21 2025

Aside from some cirrus streaming overhead this afternoon, it`s
been a pleasant day with decent warming - especially in nearly
snow-free areas. Temperatures range from the lower 20s in
Wisconsin to lower 40s across parts of southwest Minnesota with
another hour or so of warming to go. Clouds will continue
increasing this evening and a band of isentropically-forced
precipitation will begin breaking out across western Minnesota
around midnight, then track east overnight to Wisconsin early
Monday morning. The lower levels of the atmosphere will be quite
dry initially and warm. As the isentropic lift increases and
the band becomes healthier, precipitation will cool the lower
atmosphere and should reach the ground at least briefly before
ending. Models generally favor freezing rain across Minnesota
(except in the southwest where surface temps may remain at or
above freezing). However, wetbulb temperatures aloft per
forecast soundings also hint at sleet. Therefore, continuing
with chances for freezing rain and sleet. Unless the band
becomes quite healthy, which is a low end probability, then some
snow is also possible. In Wisconsin, thermal profiles are a bit
cooler so snow chances are higher. Some sleet may also mix in
if wetbulb temps hover near freezing, which has been the trend
today. A few models aside, QPF looks really light. Perhaps
around a tenth in Wisconsin as snow, but less than 0.05" in
Minnesota as sleet and freezing rain. Such light amounts are not
likely to have significant impacts, and if the band remains
weak, it may be hard to get much precipitation down to the
surface level at all. Issued an SPS to highlight the potential
for a few slick spots for the morning commute. Didn`t feel this
event rises to the level of an advisory yet with confidence of
widespread impacts being low. That may change this evening or
overnight though with evolving trends.

A highly anomalous mid level ridge parked over the northern Gulf
Coast will lead to mild and even warm conditions across much of
the center of the country this week. Despite 850 mb temp
anomalies of around +20C across the Upper Midwest on Christmas
Day, lingering snow pack will moderate how much we can warm.
Further, the low level inversion that results will likely lead
to widespread low clouds and perhaps fog which would further
reduce the chance to warm substantially. That may be a different
story across southwest MN where a lack of snow combined with
deeper mixing and sunshine may bring low 50s for highs.

Generally, the pattern will feature a lot of weak disturbances
across the northern CONUS stemming from the atmospheric rivers
on the west coast. These have little predictability in the
medium and long ranges. However, a more substantial wave could
eject northeast from the Rockies Christmas Day into Friday. The
degree of warm air aloft will likely mean low snow chances and
either rain or freezing rain as the preferred p-type depending
on surface temp. As the system passes, cooler air will spill in
behind it along with a the potential for a few snow showers.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1055 PM CST Sun Dec 21 2025

Very few changes to the ongoing thinking from the 00z TAF set.
VFR to start with the anticipation that a swath of wintry
precipitation will move across the region roughly in the
midnight-sunrise timeframe. Have kept the PROB30s confined to
the westernmost TAF sites (AXN and RWF), with TEMPOs going
eastward. Still looking for a primarily 3-4hr window of mainly
FZRA with either PL or SN mixed in (better chances for SN in
western WI with icy precip in central-southern MN). Liquid
totals are only expected to run between a trace to a tenth of an
inch, with icing only a trace to a few hundredths of an inch
while snow may range from a dusting to a half inch. Precip will
end over the MN TAF sites just prior to or near sunrise, with
the precip extending another hour or so beyond sunrise. Fairly
quick clearing is then expected for the rest of the day Monday.
Winds to remain SE throughout with speeds under 10kts.

KMSP...VFR into the early morning hours, then mid-level
ceilings will move into the region. Still have the TEMPO 08z-12z
for a light mixture of sleet/freezing rain. Precip looks to
continue into the morning push, then exit to the east after
sunrise with VFR conditions thereafter. A thin glaze of ice and
minor slushy sleet accumulations will be possible ending near
the start of the morning push. The rest of tomorrow will be
quiet with light southeasterly flow turning light/variable
Monday evening then westerly prior to sunrise Monday.

/OUTLOOK FOR KMSP/
TUE...VFR. Wind NW 5-10kts.
WED...VFR. Wind SE 5-10kts.
THU...VFR. Wind SE 5-10kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.

&&

$$

DISCUSSION...Borghoff
AVIATION...JPC