279
FXUS63 KMPX 171120
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
520 AM CST Mon Nov 17 2025

.KEY MESSAGES...

- Rain this evening transitions to a wintry mix of sleet & snow
  late tonight south of Interstate 94.

- A narrow band of heavier snowfall rates will likely lead to
  slushy accumulations of 1-3" across south-central & southeast
  Minnesota by Tuesday morning.

&&

.DISCUSSION...
Issued at 208 AM CST Mon Nov 17 2025

Wintry weather continues to look likely tonight as a shortwave
passes south of the area through the central plains & mid-
Mississippi valley tonight through Tuesday afternoon. The
surface low from this shortwave will remain well off to our
south, but a broad precipitation shield to its north is expected
to spread into southwest & south-central Minnesota this
evening. Dry antecedent dew points in the teens could delay the
onset of precipitation for a few hours until later tonight, &
will also likely result in a sharp cutoff wherever dry easterly
to northeasterly flow persists ahead of the wave. For now model
consensus brings this edge of the precipitation shield
generally up to the southern Twin Cities metro & I-94 corridor
through Wisconsin, & the highest probabilities for precipitation
amounts of 0.25-0.5" across southern Minnesota. High resolution
guidance continues to depict a narrow region of deformational
forcing developing tonight within the precipitation shield over
south-central & southeast Minnesota when the shortwave will be
at its strongest. Heavier precipitation amounts of 0.5-0.75" are
likely within this band, as well as where the chances are
highest for a few inches of accumulating slushy snow overnight.

The wintry precipitation forecast with this system remains
complicated, owing to surface temperatures & temperatures in
the lowest few 1000s of feet of the atmosphere hovering right
around freezing. In addition, higher dewpoints right around 32
degrees will also be advecting into southern Minnesota as the
precipitation begins, meaning the effect of dynamic wet bulb
cooling within the band of strongest forcing will not be as
pronounced. High-resolution model guidance has pretty good
agreement with the rain changing over to snow or a wintry mix
of snow & sleet by midnight, although there are a few solutions
such as the HRRR that begin the transition to wintry precip
earlier in the evening. This timing in the changeover to wintry
precipitation will play a large role on potential snow
accumulations, as the models that depict an earlier transition
show the potential for several inches of snow accumulation
given the longer duration snow would have to accumulate. Further
complicating the forecast is the likelihood for sleet to mix in
with the snow for the first few hours during the changeover to
rain to snow. "Snow"-liquid ratios for sleet are typically
around 2-3:1, compared with the expected slushy snow ratios of
7-8:1 with this event, so that too will likely knock down
potential snowfall amounts compared to some of the heavier snow
solutions that depict a clean transition from rain to snow.
Once the wintry mix transitions fully over to snow, we will see
the heaviest snowfall rates near 0.5"/hr during the overnight &
early morning hours, with the snow tapering off & ending by mid
to late morning across southeast Minnesota.

While there is still some spread in high-resolution models
regarding the transition from rain to snow & thus forecast
snowfall amounts, the 25th-75th percentile spread on the HREF &
REFS high-resolution ensembles along with the larger-scale
GEFS/EPS/& EPS AI ensembles all suggest a swath of 1-3" of
slushy snow is likely between Interstate 90 in the south and the
southern Twin Cities metro in the north. The high-end 90th
percentiles (earlier/cleaner transition to snow) from these
ensembles do suggest a chance for amounts up to 4-6" within the
heaviest band of snow, but even then the forecast model snow
depth on these high-end model solutions suggests there would
probably only be 2-4" of snow on the ground at any given time
due to compaction & melting from the warm ground & near-surface
temperatures. Since temperatures will be hovering right near
freezing through the event, & quickly rise above freezing
through the morning as the snow wanes, travel impacts from the
snow will likely be limited to when the snow is falling. However
since is the first appreciable snowfall of the year for many,
plan on a slow & slippery commute Tuesday morning from the Twin
Cities metro & south. High temperatures are forecast to reach
the upper 30s & low 40s by the afternoon so any snow is unlikely
to last long on roads & pavement by the time the Tuesday evening
commute comes along.

Beyond Tuesday, temperatures look to be on the warm-end of
normal into the weekend, with chances for light precipitation
coming Thursday as a weak shortwave skirts across northern
Minnesota. The bulk of the precipitation from this system should
remain over northern Minnesota. Another, much stronger, system
looks likely over the mid-Mississippi valley late Thursday
through Friday, but ensemble guidance continues to keep even the
northern fringes of the precipitation shield with this system
to our south over Iowa.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 520 AM CST Mon Nov 17 2025

Today will be VFR with a persistent mid level cloud deck.
Winds will increase with some gusts as high as 20 knots from the
southeast today at western Minnesota terminals. The main impact
of this period comes tonight into tomorrow morning. Rain will
move into southwest Minnesota tonight impacting mainly RWF and
MKT. This rain transition to a wintry mix and eventually by
tomorrow morning snow. Mainly MVFR impacts but, an area of
moderate snowfall with IFR visibility is likely somewhere. Just
not enough confidence yet that it will occur at either terminal
for inclusion in the TAF. Near the end of this forecast period
precipitation will come to an end. MSP and EAU are on the edge
of the precipition for this event. Both could see some snow
accumulate or could end up with nothing as there will likely be
a sharp cutoff in rain and snow along the north edge. What is
more likely for these two sites is, that regardless of
precipitation, lower MVFR ceilings are likely.

KMSP...East winds to start the day causing a slight crosswind
component for the parallels. This wind will shift more to the
southeast later in the morning for a more ideal direction for
the parallels. Winds should remain at or under 10 knots
sustained today. The big question for MSP remains will
precipitation reach the terminal? MSP looks to be on the
northern edge of the chances, so opted to put some MVFR -RASN
into the TAF. However it is just as likely that this stays just
to the south of terminal area. So we will be keeping a close eye
on where this sets up for future TAF issuances.

/OUTLOOK FOR KMSP/
WED...MVFR, IFR CIGS possible. Wind S 5-10 kts.
THU...MVFR. -SHRA possible. Wind SE bcmg NW 5-10 kts.
FRI...VFR. Wind N 5-10 kts.
&&

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

&&

$$

DISCUSSION...ETA
AVIATION...NDC