textproduct: Sioux Falls

KEY MESSAGES

- A series of weak systems will move through the region over the next few days, mainly north and east of the area. The best chance of precipitation locally with these systems will be on Wednesday, with a 30-50% chance of measurable precipitation focused over southwest Minnesota.

- A chilly New Year's Eve is in store for our area, with temperatures around midnight that night ranging from the single digits over southwest Minnesota to near 20 degrees in south-central South Dakota.

- We'll see a return to above-normal temperatures tomorrow, but drop back down to seasonal temperatures through the remainder of the week. Temperatures warm-up again this weekend with highs mainly in the 30s and 40s by Saturday.

DISCUSSION

Issued at 222 PM CST Mon Dec 29 2025

It's a chilly, but mostly sunny afternoon on this Monday as temperatures have only managed to climb to the upper-single digits over southwest Minnesota to the low-20s in south-central South Dakota. Winds have been coming down through the afternoon, and this is thanks to a high pressure system settling into the area. Winds remain light tonight and with snow cover across much of the area, temperatures will drop quickly after sundown. However, warm air advection increases late tonight ahead of a weak upper-level wave that will move out of southern Canada into far northern Minnesota. This means we'll see our lows reached around midnight and then temperatures will hold steady late tonight and even rise as we approach sunrise. So low temperatures tonight will be in single digits to teens, but temperatures around sunrise tomorrow will be in the upper-teens to 20s.

The aforementioned upper-wave will pass through central Minnesota and head towards the southern Great Lakes through the day tomorrow. The best ingredients for precipitation with this system will remain north and east of the area, but some guidance shows some precipitation creeping into parts of southwest Minnesota. Soundings show just enough dry air below the cloud layer that even if we did see some radar returns tomorrow, the activity likely wouldn't make it to the ground. All that to say, left the forecast dry for tomorrow though trends will be monitored. A mild day is expected for our Tuesday with highs mainly in the 30s across the area, though the mostly snow-free areas of central South Dakota will see some highs in the 40s. Winds gusts will be up to around 25-30 mph tomorrow, which could lead to some patchy blowing/drifting snow in areas with the greatest snowpack. Widespread issues are not expected.

Since we'll be stuck under northwest flow aloft, another disturbance will dive out of Canada on Wednesday and this one has a slightly better chance of impacting the area (though still not expecting anything significant). Once again, any areas of precipitation look to mainly affect southwest Minnesota, with NBM probabilities of measurable precipitation around 20-40% along and northeast of a Jackson to Hendricks line. Looking at other ensembles, the EC and EC AI ensembles are more in line with the NBM while the GEFS is an outlier and shows much higher probabilities up to 70% in and around Marshall of at least 0.01" QPF. One thing the ensembles do have in common is the fact all of them show a sharp gradient of probabilities from northeast to southwest of this measurable precipitation. For example, the GEFS has a 70% chance of at least a trace of QPF in Marshall; but in Pipestone, around 45 miles southeast of Marshall, the probability is only around 20%. So the amount of precipitation we see with this system will be highly dependent on its ultimate track, which won't get resolved until we get some more of the higer-resolution guidance in. For now, will carry the 15-35% PoPs for Wednesday, mainly focused over southwest Minnesota. Precipitation-type looks to be predominately snow, though soundings indicate perhaps a small warm-nose that would lead to light freezing rain. Confidence in this potential is not high enough to include in the forecast at this time due to high uncertainty regarding the strength and depth of this warm-nose. Snow amounts if any will be light, likely a few tenths at best as ensemble probabilities of a half an inch of snow is less than 20%. Otherwise, Wednesday will be seasonal, with highs ranging from the mid-20s in southwest Minnesota to the upper-30s to low-40s along the Missouri River Valley.

New Year's Eve will be chilly as high pressure settles in once again, with lows heading into New Year's Day morning ranging from near zero in southwest Minnesota to the upper-teens in south-central South Dakota. Winds will remain light though, so only expecting slightly colder apparent temperatures whenever any light wind does blow. Believe it or not, another upper-wave is set to move across the region, but this one looks to be much farther north of us this time and so precipitation is not expected with it here. The upper-level trough responsible for all these quick-moving systems will slide a bit farther east to close out the work week and this will allow for ridging aloft to build into our area. This will help usher in some warming temperatures heading into the weekend. Highs on New Year's Day and on Friday will be mainly in the 20s and 30s. By Saturday and Sunday, we'll see highs warm up to the 30s and 40s. Guidance indicates the ridge breaking down a bit Saturday night into early next week and as such, a few shortwaves move across the area. However, ensemble probabilities of measurable precipitation with these systems currently suggest the better moisture will be north of the area.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1040 PM CST Mon Dec 29 2025

VFR conditions expected through the period, with lower VFR stratus working its way in toward the end of the period. Could see some MVFR stratus across southwestern MN Tuesday evening, which may expand southwest after the period ends.

Winds remain light and variable into Tuesday morning. Marginal LLWS is expected across the area Tuesday morning with the northwesterly LLJ around 35 knots. Conditions are marginal with speed shear, but directionally exceed 30 degrees as surface winds are slower to shift northwesterly and strengthen late in the morning. Afternoon wind gusts around 20 knots may lead to some patchy blowing or drifting snow. Significant or widespread impacts not anticipated.

FSD WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None. IA...None. NE...None.