486
FXUS63 KMPX 172119
AFDMPX

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
319 PM CST Wed Dec 17 2025

.KEY MESSAGES...

- Snow showers, gusty northwest winds of 40-50 mph, & plummeting
  temperatures behind an Arctic front tomorrow morning through
  the afternoon.

- Winter travel impacts expected from a combination of the gusty
  winds causing low visibility in blowing snow, & flash freeze
  conditions causing icy roads & surfaces.

- Precipitation begins this evening as light rain spreads
  eastwards across the area, ending overnight as a dry slot
  moves through the region.



&&

.DISCUSSION...
Issued at 241 PM CST Wed Dec 17 2025

Active weather over the next 36 hours as an anomalously strong
low pressure for December tracks along the US/Canada border.
Currently, our system is located over eastern Montana/southern
Saskatchewan, & near its peak strength of 980 mb. The low should
maintain this intensity as it skirts eastwards along the
US/Canada border through the Dakotas & Great Lakes tonight
through tomorrow, making it one of the stronger systems we have
seen in the Dakotas/Minnesota for mid-December. Warm air
advection continues ahead of the approaching surface cld front
his afternoon, with all locations already above freezing &
expected to warm even more into the upper 30s & low 40s by the
time precipitation arrives this evening. This should make our
precipitation type forecaster much cleaner than prior forecasts,
as temperatures look to be warm enough for a few hours of light
rain as the first wave of precipitation moves through the
region with the occluded front this evening into late tonight.
Localized freezing precipitation can`t totally be ruled out
across portions of western Wisconsin this evening, where
stubborn pockets of sub-freezing temperatures could still
exist, but warming temperatures through the night will quickly
mitigate any small threat for ice.

The rain we get will be light, on the order of 0.10-0.25", &
ends after a few hours overnight as the deep & occluded low
pulls a well-defined dry slot through the Upper Midwest. Gusty
south winds of 30-40 mph with the rain this evening will slacken
as this dry slot moves through the area, with these relatively
benign conditions continuing into at least the early morning,
but most likely the entire morning commute across the area.

Conditions drastically change through the morning however, as
the Arctic front on the back side of the low pressure moves
through Minnesota & Wisconsin. Strong cold advection with the
front will lead to plummeting temperatures through the day as
well as very gusty northwest winds, with gusts up to 50 mph
likely through the afternoon. Light snow is also expected behind
the front in the wrap- around region of the low, with localized
bursts of heavier snow likely in sporadic snow squalls. We are
only expecting snowfall amounts on the order of an inch or less
with this light snow, but the gusty winds coupled with the
falling snow will likely lead to periods of low visibility.
Additionally, temperatures quickly falling into the single
digits & below zero through the afternoon will likely lead to
icy flash freeze conditions as whatever snow that falls in
addition to any antecedent moisture quickly ices up on roads &
other surfaces. We decided to issue a Winter Weather Advisory
across most of central Minnesota, the Twin Cities metro, &
western Wisconsin, for the aggregate of these travel hazards,
as the combination of lower visibility & flash freeze
conditions are expected to lead to hazardous driving conditions,
especially for the evening commute.

The light snow will wrap up through the evening along with the
winds weakening, but continued cold advection will continue to
drop temperatures below zero into Friday morning. Lows around
-10 are expected across central Minnesota with lows near zero
 elsewhere, while wind chills values will approach -25 across
 central Minnesota. We`re still not quite out of the woods with
 wintry precip Friday, as a shortwave on the heels;ls of our
 departing system could generate a light swath of a wintry mix
 of snow & freezing drizzle across central Minnesota & western
 Wisconsin. Strong zonal flow then sits over the northern tier
 of the CONUS into next week, which should prevent any major
 winter systems over the region for the foreseeable future.
 However, any subtle waves within the jet could create chances
 for light precip, so we may see multiple nuisance chances for
 light snow over the weekend & into next week. Temperatures look
 to remain fairly reasonable give the zonal flow, but we will
 likely stay of to the north of any potential warm airmasses
 given the jet overhead.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1200 PM CST Wed Dec 17 2025

VFR through this afternoon with winds increasing out of the
southeast. A potent surface low is forecast to track east out
of the Dakotas and strengthen as it moves through through
northern MN tonight. A rather pronounced wind shear scenario is
forecast to develop in response to this evolution. Have included
several hours of LLWS at each terminal in conjunction with the
timing of strong southwesterly mid-level winds moving over the
strengthening southeasterly surface winds (forecast to gust
upwards of 35+ kts). A band of rain will move from west to east
ahead of the system`s cold front and will likely produce MVFR
visibility for a couple hour period at each terminal. The 18z
TAFs capture the arrival time of rain at the western MN
terminals starting at roughly 2-3z, the eastern MN terminals
around 4-5z, and into western WI by 6-7z. A wedge of dry air in
the lowest level of the atmosphere may delay the onset of the
most persistent rain/lowest visibility. This round of
precipitation should be all rain for the majority of the
terminals, however strong cold advection may allow for a mix of
freezing drizzle to rain and snow across the WI terminals.
Confidence was highest in this at EAU, where at TEMPO for
freezing drizzle was included.

Winds are forecast to diminish slightly and ceilings will
improve following the passage of the cold front and conclusion
of rain/mixed precipitation. This is due to the system`s dry
slot moving over the region by daybreak Thursday morning. The
second chapter of the dynamic system will bring wrap around snow
and strong WNW winds (Gusts 35-40+ kts) to the region late
morning into the afternoon. Snow accumulations generally should
remain at an inch or less, but the convective "burst" nature to
the snow showers will promote a period of up and down visibility
and the combination of strong winds, plummeting temperatures,
and falling snow may lead to the quick development of icy
conditions at all of the terminals through tomorrow afternoon.

KMSP...Main focus through the first portion of the TAF will be
the development of strong LLWS late afternoon through this
evening. Rain arrives around ~5z with a period of MVFR
visibility associated with the rain through roughly ~9/10z.
Should have a quiet period Thursday morning, followed by the
return of precipitation chances (this time in the form of snow)
which may accumulate up to 1" tomorrow afternoon. Have included
a PROB30 to capture the timing of snow impacts. This looks to be
one of those winter scenarios where MSP will be in and out of
the lower visibility as heavier bursts of snow showers move
through. Strong WNW winds are forecast to gust upwards of
35-40kts tomorrow afternoon.

/OUTLOOK FOR KMSP/
FRI...VFR. Wind SE 10-15G25kts.
SAT...VFR. Wind NW 10-15kts.
SUN...VFR. Wind W 5-15kts.

&&

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

&&

$$

DISCUSSION...ETA
AVIATION...Strus