textproduct: Twin Cities

KEY MESSAGES

- A couple of light snow events today; this morning west of I-35 and this afternoon and evening across central MN and northwest WI.

- Strong system Tuesday to bring an intense and narrow band of heavy snow. 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.

- Strong winds are expected Tuesday evening southwest of the low track, with gusts of 40-50 mph possible south I-94 in Minnesota

- Cold temperatures return to end the work week with below zero temperatures likely at night. The coldest period (in terms of wind chills) will be Friday night into Saturday, with the need for Extreme Cold headlines (most likely an Advisory) becoming more likely.

DISCUSSION

Issued at 327 AM CST Mon Dec 8 2025

Strong WAA is ongoing across the area tonight, with the lows already achieved back in the 10pm to midnight window for most locations. Isentropic upglide is providing a broad region of ascent across MN. Radar has been certainly lighting up with snow returns, but we've had the ever popular slowly closing donut whole on the MPX radar as this precip is battling a very dry wedge of air around h85 that was observed on the 00z KMPX sounding last night. Based on the occasional 3/4sm visibilities we've seen in the snow, folks out in western MN will likely wake up to a fresh inch of snow this morning from this initial band of WAA snow. This band of snow is expected to lose steam though this morning, with dry air mentioned above looking to make it tough for this snow to make it much farther east than the I-35 corridor. Of course this isn't the only snow coming for today! Overnight, an intense jet streak moved across southern BC in a association with an Atmospheric River that will be unleashing a firehose of precip in the coming days on the Pac NW, and spoiler alert, will play a role in what we see Tuesday. Back to the jet streak though, there is a shortwave on nose of this jet streak that will send a surface low across northern MN this afternoon/evening. The primary band of snow (1 to maybe 3 inches) will fall north of the MPX area, but the southern end of the WAA wing of precip associated with this band will clip northern portions of the MPX area, where totals of up to 2 inches of snow will be possible from Staples, through Mora, and down to Ladysmith in WI.

The next car coming in the clipper train for Tuesday is the strongest and most complex of the waves we will have experienced since this all started Thanksgiving weekend. Where this wave differs from the rest we've see to this point is it has the strongest dynamics (150kt jet streak and a deepening surface low getting down under 990mb) and by far the highest amount of moisture. The moisture comes from the fact that this wave Tuesday will be pulling in a plume of moisture from the ongoing atmospheric river event in the Pac NW, with PWATs increasing to around 200% of normal. There's a lot to unpack with this, so lets break it down into more manageable pieces.

Low track: This will be critical in who stays all snow, who gets a mix, who stays as mostly rain, and where the strong winds come Tuesday evening. Current thinking is that we'll see a low track somewhere between the 8.00 GFS and ECMWF. The GFS basically tracks the surface low down the MN river and sets the southern extent of possible outcomes. On the northern end, you have the ECMWF, which tracks the low from Fargo to Stillwater. The NBM and our forecast (and WPC) is weighted heavily in the direction toward the ECMWF solution.

Precipitation types: this system will have a little bit of everything, but the surface low track will be key in determining p- types. Right along the low track, a mix of predominately rain and snow is expected. Just northeast of the low track will be the snow bonanza, with snow lovers southwest of the low track ending up rather disappointed, with rain becoming the predominate p-type. The current forecast, with its lean toward the ECMWF, has the rain/snow line setting up from roughly Little Falls, to Princeton, New Richmond, and Eau Claire. However, given where the ECMWF-AIFS and Canadian sit, we would not be at all surprised if this rain/snow line ends up 20 to 30 miles farther southwest of where it is currently forecast, which would put this transition line right across the heart of the Twin Cities metro. As for the freezing rain threat, this looks to primarily come in the first 2-4 hours of precipitation onset Tuesday morning before near surface WAA catches up with the warm nose aloft, giving us a question of rain or snow for the bulk of this event.

Snowfall: Though differing on low track, all of the models show a similar story for snowfall. A very intense band of snow (with 1-2 inch per hour snow rates) will develop just northeast of the low track, where total QPF is likely to be up around 0.5 inches. This should lead to a very narrow band of 5, to as much as 8 inches of snow. For the southern GFS solution, that would put this intense band of snow right on top of the Twin Cities metro. For the northern ECMWF, that band of heavy snow would take in a tour of the falls from Little Falls, to Taylors Falls, to Chippewa Falls.

Winds: If you end up southwest of the surface low, it won't be smooth sailing. Here, it looks like a fairly classic stinger jet setup, which will result in fairly intense wind gusts Tuesday evening as the low tracks across central MN into western WI. Looking at peak wind gusts from the EPS at Granite Falls, there are 13 members that have gusts there of over 50mph, so there's a pretty high ceiling (55 mph) for wind gusts from west central through south central Minnesota. For the wind forecast Tuesday night, we did go with 90th percentile winds from the NBM, but we could end up a bit higher on speeds than even the 90th percentile. Eventually, we will need wind headlines to go with winter headlines Tuesday night.

Winter Storm Watch: the initial proposed Winter Storm Watch from WPC largely kept a Winter Storm Watch northeast of the Twin Cities metro. However, given what we've been seeing the last several runs of the ECMWF-AIFS (which has been frankly crushing it with correctly placing where the heaviest snow will fall with all of these waves going back to Thanksgiving weekend), we felt more comfortable giving this watch a little more breathing room to the southwest. So even though our current snow forecast wouldn't support the watch coming through Douglas, Stearns, Ramsey, and Pepin counties, we brought it down to those counties with the expectation that a southward drift in the snowfall forecast is likely in the next 24 hours.

For the rest of the week into next weekend, it will be very cold once again as another arctic high noses in from Canada. The coldest weather looks to come Friday through Sunday, when highs will struggle to get above 10, with lows in the single digits and teens below zero. The forecast continues to highlight wind chill values down in the 25 to 35 below zero range Friday night through Saturday morning, so it continues to look like we'll eventually need our first extreme cold headlines of the season to kick off the weekend. Although it will be cold and dry, there will be more opportunities for light snow as weak waves continue to rip through the area in the northwest flow. These would get us back to our 0.5" to 2" dustings we've become accustomed to over the past week. Right now, we see potential for these little dustups Thursday/Thursday night, Friday, and again on Saturday. For those that have had enough of this cold and half inch snows, early signs for next week is that we'll see the storm track shift north some, allowing for an easing of the cold and maybe more than 18 hours between snow events.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 503 AM CST Mon Dec 8 2025

Two rather intense, but narrow snow bands are currently stretching from just west of the Twin Cities into southeastern MN. These bands will keep moving east, likely affecting MSP and RNH within the first few hours of the TAF period. Have added TEMPOs for -SN, IFR visibilities, and reduction to MVFR cigs for these terminals. A quick inch of snow may be possible. These bands should dissipate as they continue into WI. Cigs will gradually fall to IFR/LIFR from west to east throughout today. Best chance for LIFR cigs will be over central MN where a passing clipper system will bring a few hours of -SN. Have also added a TEMPO at AXN, STC, RNH, and EAU for visibilities down 2-3sm as the clipper moves from west to east this afternoon and evening. Cigs will likely remain stagnant at IFR/MVFR through tonight, except at RWF where scattering clouds should cause improvement to VFR. Southerly winds will near 10 knots this afternoon and evening before switching to westerly and slowing to near 5 knots tonight as a cold front passes.

KMSP...Added TEMPO from 12-13Z for -SN, visibilities to 2sm, and MVFR cigs. Cigs should fall to MVFR this morning and then IFR early this afternoon. Added PROB30 from 23-03Z for -SN and IFR cigs with passing clipper system to the north. IFR cigs likely for at least a portion of tonight before improvement occurs Tuesday morning.

/OUTLOOK FOR KMSP/ TUE...VFR early, MVFR/IFR late with -RASN. Wind S 10-15G30 kts. WED...MVFR/IFR. Chc -SN. Wind NW 10-15G25 kts. THU...MVFR. Chc -SN. Wind NW 10-15 kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...Winter Storm Watch from Tuesday afternoon through late Tuesday night for Anoka-Benton-Chisago-Douglas-Isanti-Kanabec- Mille Lacs-Morrison-Ramsey-Sherburne-Stearns-Todd- Washington. WI...Winter Storm Watch from Tuesday afternoon through late Tuesday night for Barron-Chippewa-Dunn-Eau Claire-Pepin-Pierce- Polk-Rusk-St. Croix.