textproduct: Sioux Falls

KEY MESSAGES

- A band of light to moderate snow is expected to arrive this afternoon. Moderate to high confidence of widespread light accumulations trace to 2", with potential for 2-4" near and just south of I-90.

- Light snow is expected again Wednesday, but also the potential for 30 to 45+ mph winds in the afternoon/evening. Winds could lead to significant blowing snow issues. Confidence is moderate and will need to see how much snow falls today to get a better feel for the extent of the blowing.

- Dangerous and life-threatening cold expected to arrive for the end of the week and start of next weekend.

DISCUSSION

Issued at 225 AM CST Tue Jan 20 2026

Deep low pressure across central Canada will turn upper level flow more northerly and rotate a pair of waves southward today and Wednesday. The initial wave today is not quite as strong, but does have some moisture to work with and as the wave collapses south this morning allows mid level flow to turn a touch west southwest which increases frontal forcing across the area. Currently looking like somewhere from about 800mb to 700mb will be the better focus with more preferable temperatures in that layer, especially near the top of that layer. This should allow a band of snow to rapidly develop late this morning into early afternoon and continue into the evening. Some disagreement on placement of the band where the longest duration of moderate snow will fall but somewhere near and just south of I-90 looks like the area best collocated with the strong frontal forcing and best thermal profile. As has been advertised with this system today, wind should not play much of a role so will be focusing on snowfall amounts. The latest higher resolution models are fairly agreeable on placing the higher snowfall amounts across I-90 in southwest MN into parts of northwest IA, while the lower resolution ensemble output is a touch farther north and lighter. The main message from this new data is that nothing major changes other than the higher snowfall amounts may be a bit south from previous data with a trace to 2" over much of the area with the potential for a small band of 2-4" somewhere near and south of I-90. The forcing should exit the area mid to late evening with very little after about midnight tonight.

The break from this system to the next will be fairly short, with the Wednesday system showing the potential for higher impacts due to some very strong winds expected. Most models suggesting wind gusts on Wednesday of around 50 mph, but there are some pushing 60-65 mph. With the potential for a fresh 1-3" of snow and an additional half an inch to inch of snow Wednesday morning, brief whiteout conditions will again be possible, especially if we start pushing closer to 60 mph. A fairly strong PV pushes through on Wednesday morning with very strong cold air advection settling in late morning into the afternoon which will help drive a deeper mixed layer with some instability tapping into the dgz which may allow for additional snow showers through peak heating. The main story for Wednesday is to be prepared to make changes to travel plans if we have a widespread enough snowfall today which will provide the Wednesday strong winds with more snow to blow around.

A broad and cold trough settles into the area behind this wave with much below normal temperatures Thursday through Sunday. Some hints that this trough will break down with temperatures closer to normal early next week. Wind chill values Thursday night into Friday night will likely range from about -20 to -40, then modify a touch Sunday and average -5 to -15 in most locations.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 500 AM CST Tue Jan 20 2026

The morning should remain VFR for the entire area, in fact this should continue through mid afternoon for most locations. During the afternoon a band of snow will develop with the better chances for MVFR and IFR conditions near I-90 in SD in the afternoon and into parts of southwest MN and northwest IA late inthe afternoon and the evening. Conditions will improve back to MVFR for most locations from late evening into the overnight hours.

Beyond this TAF period, Wednesday will bring very strong northwest winds and snow showers with reduced visibilities in snow and blowing snow looking likely. Stay tuned.

FSD WATCHES/WARNINGS/ADVISORIES

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