883
FXUS63 KMPX 042040
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
240 PM CST Thu Dec 4 2025

.KEY MESSAGES...

- Accumulating snow and slick travel conditions likely along and
  north of I-94 Friday. Snow amounts of 1-3" are expected.

- Another storm system will produce accumulating snow and
  travel impacts across southern MN on Saturday.

- Sub-zero morning lows return for the end of the weekend,
  followed by yet another storm system with the potential for
  mixed precipitation early next week.

&&

.DISCUSSION...
Issued at 240 PM CST Thu Dec 4 2025

Our first widespread sub-zero morning of the cold season saw
temperatures dip as low as -15 or so across portions of central MN.
Fortunately, the duration of the coldest air is rather short-lived
thanks to an increase in southerly winds this afternoon. The center
of the Arctic high that supported the early December cold blast has
drifted southeast over the southern Great Lakes. Mid-level warm
advection is ongoing within a tightening pressure gradient to the
west of the surface high and south of a clipper currently digging
into northeastern MN. Surface temperatures are inching closer to the
double digits above zero with each passing hour and look to run in a
non-dirunal pattern through the rest of the night. In other words,
evening temperatures in the low teens will be cooler than the
temperatures around daybreak Friday, which are forecast to be in the
low 20s.

Our attention turns to an active clipper train that is ongoing
within the northwesterly flow aloft. Much of the precipitation
associated with the aforementioned clipper will remain north of our
forecast area tonight, though portions of western WI may see
some flakes from this wave. Confidence has increased that a
trailing clipper, currently crossing the International border
over MT, will dig southeast across the Dakotas tonight and bring
accumulating snow to the region tomorrow. There is still some
uncertainty with the track of the clipper, as evidenced by the
12z guidance suite. Most of the HREF members and the operational
RAP advertise the main swath of snow tracking along and north
of I-94 through central MN. On the other hand, there are some
guidance members (AIFS/operational Euro) which are a bit farther
south with the main swath and place the main band of snow from
say Swift county to the ESE through the heart of the Twin
Cities. Despite this uncertainty in the exact track, the upward
trend in QPF and deep saturation on forecast soundings has resulted
in an uptick in the snow forecast (1-3") and PoPs (Now 70-80
percent across central MN) through the day tomorrow. Our snow
forecast is a product of up to ~0.1-0.15" liquid in the main snow
band and event SLR`s ~15:1, which supports the 1-3" range. While
somewhat muted, there looks to be at least some frontogenic component
to the forcing in the 850mb level, so the potential for a localized
band of 2-4" does exist (and right now looks to be most likely
along the WFO MPX/DLH border. Snow is forecast to begins across
west central MN shortly before daybreak and continue to spread east
through the morning. Average snowfall rates between 0.25"-0.5"/hr
(per the HREF) will support the potential for travel conditions
to become slick through the morning. Snow will end from west to
east tomorrow afternoon, but it is likely that locations under
the heaviest band will still have some slick spots for the
evening commute. Finally, forecast soundings across south/southwestern
MN illustrate the loss of cloud ice in association with mid-
level dry air. With synoptic lift present, we could see a localized
freezing drizzle scenario develop. We have opted to leave any
mention out of the grids this afternoon, however we`ll treat
this part of the forecast as a bit of wild card tomorrow.

No headline is planned at this time, though we`ll leave the
potential for a short advisory on the table depending on what the
evening/night shift observes in the 18z/00z model suites.

The forecast remains active heading into this weekend as a Pacific
influenced shortwave digs southeast along a baroclinic zone from MT
towards IA. Guidance has come into better agreement with the
anticipated track of the wave which supports a swath of accumulating
snow from eastern SD/southwestern MN/northern IA. Since this system
has more of a Pacific influence to it, it`s no surprise to see
higher moisture content resulting in a greater potential for
accumulating snow. An initial call would support 3-5" of snow along I-
90, with amounts falling off to about a half inch to an inch as far
north as the Twin Cities. Folks traveling south this weekend should
keep an eye on the latest information as travel is likely to be
impacted from falling/accumulating snow. The low is forecast to
continue to the southeast towards the Ohio Valley. As this occurs,
northwesterly flow will usher in another anomalous air mass from
southern Canada which will drop surface temperatures below zero
Sunday and Monday morning. It`s likely that Sunday`s afternoon highs
will struggle to warm above the single digits!

Our very active upper level pattern will send another storm system
into the northern CONUS in the Tuesday/Wednesday timeframe. Mid-
level warm advection of a thermal ridge will warm temperatures to
near/above freezing at 925/850mb heading into Tuesday. Should these
trends continue, the Tuesday/Wednesday system will likely have some
p-type issues given the marginal nature of the thermal
profiles. Plenty of time to better define the setup, but one
things is for sure: Our forecast remains active and wintry
through at least mid- December!

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1130 AM CST Thu Dec 4 2025

Clouds are beginning their approach ahead of our Clipper system.
KAXN has already gone MVFR and KRWF should follow shortly. MVFR
cigs will continue to spread east through this afternoon for our
Minnesota terminals with south-southwesterly winds 10-15kts with
occasional gusts up to 25kts. Winds decrease overnight to 10kts
or less.

Biggest change for this TAF set is that confidence has
increased in some snow by tomorrow morning for most sites.
Confidence is lower for KRWF and KMKT as the overall track for
the Clipper basically sends it right down I-94. Timing has been
a bit slower with the 12z models, so will need to monitor this
for the next cycle to see if snow onset timing needs to be
adjusted further. Expecting a solid chunk of the morning to be
IFR with the potential for some TEMPO LIFR. Snow ends from west
to east with winds turning to the northwest on the backside.

KMSP...MVFR cigs are expected by this evening and will continue
to fall overnight. Snow should hold off until after 12z,
decided to go with a 14z start time. Guidance is still a little
all over the board with start/end times, so went more
pessimistic with the snow not ending until 21z tomorrow. This
will be refined in the coming updates.

/OUTLOOK FOR KMSP/
SAT...MVFR/-SN, chc IFR. Wind N 5-10kts.
SUN...MVFR/-SN early, bcmg VFR. Wind N 5-10kts.
MON...VFR, chc MVFR w/-SN. Wind S 10-15kts.

&&

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

&&

$$

DISCUSSION...Dunleavy
AVIATION...Dye