187
FXUS63 KMPX 091648
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1048 AM CST Tue Dec 9 2025

.KEY MESSAGES...

- Strong system to bring an intense and narrow band of heavy
  snow this afternoon and evening along and north of the I-94
  corridor. The rain/snow line looks to setup over the Twin
  Cities metro, with a strong snowfall gradient expected from
  southwest to northeast across the metro.

- A 2-4 hour period of freezing rain/drizzle will be possible
  along and just south of the I-94 corridor as precipitation
  initially moves in today.

- Strong winds are expected Tuesday evening southwest of the
  low track, with gusts of 40-50 mph possible south I-94 in
  Minnesota. Uncertainty remains high with how blowable the snow
  pack in southwest Minnesota will be after they see highs
  above freezing with rain and drizzle today.

- Multiple bouts of light snow will be possible Wednesday
  through Saturday. Only minor accumulations would occur with
  any additional snowfall we see after today.

- Very cold temperatures settle in by this weekend with wind
  chills approaching advisory criteria Friday night and Saturday
  night.

&&

.UPDATE...
Issued at 1048 AM CST Tue Dec 9 2025

As of 10AM this morning, our sfc low which is driving
today`s wintry mess was located in northwestern North Dakota and
moving east-southeastward. The forecast remains on track with the
eastern periphery of the precipitation shield now making its way
into western MN. Light snowfall rates this morning will increase to
1.0-1.5"/hour, especially along and north of the I-94 corridor as
early as 2 to 3 PM this afternoon and persisting through the evening
commute. Farther to the southwest, including the Twin Cities metro,
a short period of freezing rain mainly between 2-4 PM is expected to
occur prior to transitioning to all snow after 6 PM. Across SW`rn
MN, cold rain will transition to freezing drizzle this evening and
then change over to all snow tonight. With wind gusts approaching 50
to 55 mph, potential blowing snow could make traveling very
difficult.

&&

.DISCUSSION...
Issued at 320 AM CST Tue Dec 9 2025

As one clipper exits stage right over Lake Superior, the next one as
already queued up just off stage. Water vapor imagery shows a deep
plume of moisture coming off the northeast Pac and across the Can/US
border into the Dakotas. Within this plume of moisture, a
shortwave currently over southern Albert deepen and dig south
through the day. This is what will result in the deepening
surface low moving across MN this afternoon/evening. Spread
remains higher than normal in the models for being within 24
hours of storm onset with the eventual track of the surface low.
In a broad sense, we have a southern camp and a northern camp.
The southern camp is where you will find the majority of your
traditional deterministic models (GFS, ECMWF, Canadian...),
ensemble systems, and AI driven models. The northern camp is
almost being completely driven by CAMs (HREF). For this update,
we continue to favor an ECMWF AIFS/EPS solution, with not much
weight put into the northern, CAM driven solution. The biggest
reason for this is recent verification, with the AIFS in
particular performing very strong in correctly placing where
heavier precip swaths end up going back to the pre-Thanksgiving
winter storm. The resulting forecast is still very complex,
with a threat for an initial burst of freezing rain, heavy snow
this evening, then strong winds and potential for blizzard
conditions tonight.

Initially this morning, we will have to deal with some very minor
freezing drizzle with saturated low levels that are experiencing
lift from WAA. There have been lots of BR (mist) reports from the
airports overnight, which is a classic freezing drizzle signal,
which is what the human observes have been noting all night at MSP.
This bout of freezing drizzle will diminish when a location sees
winds switch to the northwest, which will cutoff the WAA, at least
momentarily. Precipitation will be moving quickly into western MN by
the late this morning. As this band of WAA driven precip moves
in, warm noses in soundings confirm what we are seeing with
model p-type depictions, with a 2-4 hour window at precipitation
onset where the predominate p-type will likely be freezing rain
basically along and just south of the I-94 corridor. Although
any ice accumulations are minor, there is some higher end
potential out toward Alexandria and Glenwood in northwest
portions of our CWA where ice accumulation over a tenth of an
inch will be possible. After this initial burst of
precipitation, it becomes a rain or snow question based on
surface temperatures. Given it`s heavy inclusion of CAMs, the
NBM looks too aggressive with how far northeast it drives the
freezing line this afternoon/evening and we used hourly
temperatures from the GFS to help suppress this warm nose from
the NBM. This resulted in a rain/snow line basically setting up
from Glenwood, to Minneapolis and Durand in western WI. Besides
the warm temperatures, the I-94 corridor will also be about
where the mid-level dry slot terminates, so not only does the
I-94 corridor have to deal with uncertainty in terms of the
thermal environment on p-types, but there will be issues with
cloud ice being present as well. The highest snow totals are
expected to fall just north of where the freezing line and
termination of the mid-level dry slot ends up, which right now
would place Long Prairie to the northeast Twin Cities metro and
Chippewa Falls, WI in the most likely region to cash on the snow
amounts around 7 inches. These higher snow amounts will be
driven by a heavy band of snow, where snowfall rates of near and
above 1 inch per hour will occur in a 4-6 hour window (centered
in the 5-10pm timeframe). With this continued southward drift
in where the heaviest snow is expected, we did add Washington,
St. Croix, Dunn, and Eau Claire counties into the Winter Storm
Warning.

As for the Winter Storm Watch for Blizzard conditions, we decided to
leave that as is. What is certain is that we`ll see wind gusts of 40
to 50 mph (plus a few 50+) from west central through south
central MN from roughly 1z through 8z (7pm through 2am). What is
much less certain is how blowable that snow will be coming off
a day where highs make a run at 40 with periods of rain and
drizzle as well. Looking at the WSSI for blowing snow, it
doesn`t even show minor blowing snow impacts across southwest
MN this evening. This region will likely see additional light
snow, but that does not look to arrive late in the night Tuesday
night, after the strongest winds have moved through. Although
you can`t rule out ground blizzard conditions, there are too
many question marks in place to be putting out a headline
(Blizzard Warning) that would have the effect of shutting down
southwest MN tonight. Unfortunately, we`re not really going to
know how this snow will behave until we hit it with these winds.
At the moment, there`s too much of a chance that we just get
some minor blowing, but not enough lofting of snow particles to
create the visibility restrictions needed to support a blizzard.

After this system, it`s back into the deep freeze through next
weekend. The coldest day looks to be Saturday, when a high of zero
looks like it will be difficult to attain everywhere in the MPX
area. This will also see wind chill values down in the -25 to -35
range Friday night/Saturday morning and again Saturday night/Sunday
morning, with the need for at least Extreme Cold Advisories
both periods looking all but certain. Besides the cold, there
will be more chances for light snow. Wednesday looks like your
typical snow shower setup as we have well mixed boundary layers
that have thermal profiles completely withing the dendritic
growth zone. Thursday, a weak upper wave will move along the
thermal gradient, laying down a quick band of light snow. Right
now, this looks most likely to impact Iowa into southern MN.
Friday, we should see another round of light snow move through
with the passage of the arctic cold front. Saturday brings yet
another wave embedded in the northwest flow that will work with
the strong thermal gradient to create another swath of light
snow, which at the moment is again favored for Iowa or southern
MN.

Next week, a pattern shift still looks to be upon us as we see the
eastern Canadian trough push into the north Atlantic, which
allows upper ridging to move into the central CONUS. This looks
to result in the active storm track shifting to the north, with
milder Pacific airmasses moving in, with the cold easing as
well. There`s lots of snow to our south across Iowa, so it will
be tough for us to warm significantly, but we`ll take highs
returning to the 20s and 30s for a little bit of a reprieve from
the deep winter cold.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 531 AM CST Tue Dec 9 2025

LIFR/IFR will persist over eastern MN and western WI into early
this morning as low stratus and mist are slow to move east. A
brief improvement will occur late this morning into this
afternoon. However, our next system will move southeast across
the area today into tonight bringing wintry precipitation,
strong winds, and low clouds. Snow is most likely at AXN, STC,
RNH, and EAU with snow fall rates being heavy at times,
especially Tuesday afternoon and evening. 1" per hour snowfall
rates could last 2-4 hours with accumulations near 4-7". MSP
will have a chance of seeing a wintry mix at precipitation onset
before changing over to snow with some periods of rain. RWF and
MKT could also see a wintry mix at first but will change over to
rain until late tonight when temperatures finally cool enough
for snow. Conditions should be at best IFR with reductions to
LIFR likely (with even VLIFR possible) during periods of
heaviest snow. Southwesterly winds turn southerly in advance of
the system then quickly turn northwesterly as the system and
cold front pass. Winds will become very strong this evening and
tonight with sustained values of 15-25 knots and gusts of 30-40
knots. Strongest winds will be across western and southern MN.

KMSP...Expecting a brief period of LIFR from 14-18Z as cigs fall
to near 300 feet and mist occurs. Cigs improve IFR after but
precipitation onset should be near 20Z with a wintry mix to
start. But, using latest guidance, leaning more towards snow
being the dominant precip type after 23Z. Visibilities could
drop to 1sm during heaviest precip while cigs hover near 500
feet. Snow should end by 12Z Wednesday. Expect the southerly
winds this afternoon to shift northwesterly near 02Z. Winds
will be strongest overnight with sustained values nearing 20
knots with gusts of 30-35 knots.

/OUTLOOK FOR KMSP/
WED...MVFR/IFR. Chc -SN. Wind NW 10-15G30 kts.
THU...MVFR. Chc -SN. Wind NW 5-10 kts.
FRI...MVFR/SN early. VFR late. Wind NW 10-15G20 kts.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...Winter Weather Advisory until 6 AM CST Wednesday for Douglas-
     Kandiyohi-McLeod-Meeker-Pope-Stearns-Stevens-Swift-Wright.
     Winter Storm Warning until 6 AM CST Wednesday for Anoka-Benton-
     Chisago-Isanti-Kanabec-Mille Lacs-Morrison-Sherburne-Todd-
     Washington.
     Winter Storm Watch from 9 PM CST this evening through
     Wednesday morning for Blue Earth-Brown-Chippewa-Faribault-
     Freeborn-Lac Qui Parle-Le Sueur-Martin-Nicollet-Redwood-
     Renville-Sibley-Waseca-Watonwan-Yellow Medicine.
     Winter Weather Advisory from 3 PM this afternoon to 6 AM CST
     Wednesday for Carver-Dakota-Goodhue-Hennepin-Ramsey-Rice-
     Scott-Steele.
WI...Winter Storm Warning from 3 PM this afternoon to 9 AM CST
     Wednesday for Barron-Chippewa-Dunn-Eau Claire-Polk-Rusk-
     St. Croix.
     Winter Weather Advisory from 3 PM this afternoon to 9 AM CST
     Wednesday for Pepin-Pierce.

&&

$$

UPDATE...Dunleavy
DISCUSSION...MPG
AVIATION...CTG