textproduct: Twin Cities

KEY MESSAGES

- Chance of wintry mix late this evening into Monday morning. Minor ice and snow accumulations are possible.

- Mild temperatures and weak disturbances with low predictability are in store over the next 7 days.

DISCUSSION

Issued at 329 AM CST Sun Dec 21 2025

It's a cold start today as we welcome the first day of the Winter Solstice. The good news is that we'll begin to gain daylight for the next 6 months! Current temperatures are in the single digits given light winds and mostly clear skies. A band of stratus has moved into central Minnesota and that has allowed temperatures to "recover" from the sub-zero values a few hours earlier. This high pressure will shift east to the southern Great Lakes today with return flow ushering in warmer air that'll be here to stay through the Christmas holiday. Cloud cover will increase late this afternoon and evening as a low pressure moves into the Rockies. The warm air advection will ramp up across the Plains into the Upper Midwest this evening and will trigger precipitation to develop across E SD & SW MN. The primary forcing mechanism for this precipitation will be the isentropic upglide mentioned above. This process is when warm/moist is forced to rise as it travels along a sloping surface of potential temperature over the colder surface and results in precipitation.

While precipitation likely begins within the next 18 to 24 hours, there remains a few areas of uncertainty in the forecast. First there is a varying amount of isentropic lift across various weather models that go from a very light precipitation event with QPF of a few hundredths at best to over a half inch of QPF in the NAM/NAMnest. There is still a spread between 0.02" to 0.20" even if you remove the NAM suite. That could be the difference between a non- event and an impactful winter system. The next uncertainty is the precipitation type. This broad warm air advection will result in a warm nose between the DGZ & surface. Guidance varies on how warm that layer will be that could be the difference between predominantly snow versus freezing rain. It also varies on how dry that layer is prior to saturation. Drier layer would lead to cooler temperatures in the column, but we'd likely lose some QPF potential given more of it would be sacrificed to evaporation aloft. We have opted to maintain the general idea from the previous forecast. Surface temperatures should be above freezing across SW MN that will result in primarily rain. As the precipitation moves east it will encounter cooler & drier air that will result in additional cooling as temperatures go towards the wetbulb temp. There is a good possibility of the column remaining at or below freezing and result in mostly snow across eastern Minnesota. The WAA will cause our p- type to shift to a wintry mix with freezing rain and/or sleet mixing in on the back side of the precipitation shield across eastern & central MN. Snow should be the dominant p-type as precip moves into western Wisconsin so there is higher confidence on the p- type for W WI.

For Minnesota: QPF will be generally a few hundredths to a tenth of an inch. This will support a half inch to an inch of snow across portions of central & eastern MN. Snow to liquid ratios will not be particularly impressive at or below 10:1. It's important to note that we've opted for a consshort heavy blend as the NBM values are far too low (3:1 or less) and that doesn't make sense conceptually. Light freezing rain & sleet may lead to a glaze of ice as well.

For Western Wisconsin: QPF will be around a tenth of an inch and lead to around an inch of new snow... BUT if a stronger forced solution verifies, we could see QPF values increase up to two tenths to a quarter of an inch. Snow totals would increase as well with 1 to 3" on the table as the high-end potential solution.

This system should not be a particularly high impact event, but any wintry precipitation falling ahead of a Monday morning commute can lead to potential travel delays so please plan ahead!

The week ahead will be dominated by an impressive mid level ridge that builds in over the northern Gulf Coast. This pattern likely has some staying power through the end of the month. The ridge will lead to mild and dry conditions across much of the center of the country this week. Our thaw peaks on Christmas Day across the Upper Midwest. There is uncertainty of how warm it actually gets at the surface on Christmas Day given the significant warm anomaly at 850 mb. Any lingering snow would help moderate how much we can warm at the surface. I would expect highs in the 40s unless we're able to hang onto some snowpack through Christmas Day. Locations without any snowpack will likely see highs in the upper 40s and maybe low 50s. This will mark a third consecutive Christmas with temperatures well above normal - not very festive is it? Otherwise, the pattern is controlled by the mid level ridge with the exception of weak disturbances embedded in the flow across the northern CONUS. Why are these important? Well these features aren't handled well by NWP until we're able to sample them upstream. If one of these come in stronger, it could lead to better chance of precipitation & possibly a brief cooldown similar to what happened yesterday. That's why there is less confidence in the long range forecast than normal... Happy Winter Solstice everybody.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 527 AM CST Sun Dec 21 2025

VFR with light to calm winds to start this period. Winds will pick up from the south today in the 5 to 10 knot range with increasing coverage leading to ceiling forming. These ceilings will most likely remain VFR. Late tonight snow will move in, but with uncertain coverage. So kept mostly PROB groups in TAFs for now. Minnesota terminals could also see some freezing rain mix in, but the primary precipitation type right now looks like it will be snow. For Wisconsin terminals it should remain snow throughout and confidence in more widespread snow is higher.

KMSP...VFR and light winds overall this period, but still seeing a chance for some light wintry precipitation tonight. For MSP it looks like it would fall before the morning rush and would be light with our current forecast calling for 0.1" of snow accumulation. Recent trends have been trending later though, so this could slip into the early part of the morning rush.

/OUTLOOK FOR KMSP/ MON PM...VFR. Wind S 5-10kts. TUE...VFR. Wind NW 5-10kts. WED...VFR. Wind SE 5-10kts.

MPX WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None.