textproduct: Sioux Falls

KEY MESSAGES

- Light snow is expected tonight, mostly along and north of I-90. Accumulation of less than an inch is expected, however a narrow band from Huron, to Madison, to Luverne MN may see up to 2 inches.

- A large and potentially impactful system is expected Saturday night, continuing into Monday. Near blizzard conditions are possible, and travel may become difficult to impossible. A Winter Storm Watch is in place from 7 pm Saturday until 7 am Monday. Please keep an eye on the forecast.

- Dry conditions and a warming trend is expected for the second half of next week.

DISCUSSION

Issued at 408 PM CDT Fri Mar 13 2026

Light WAA showers are moving southeast from western South Dakota. Soundings indicate a stout dry subcloud layer that will take some time to saturate before any precipitation will reach the surface. While a few light sprinkles to flurries are possible yet this afternoon, the most likely scenario is light snow will not begin until around midnight. Light snow gradually increases in areal coverage mostly along I-90 and north, gradually moving northeast through Saturday morning. There is potential for a slightly heavier band to set up as a 700 mb frontogenesis band takes shape. This band is most likely to form along a rough line from Huron, to Madison, to Luverne MN. Within this band 1 to 2 inches of accumulation is possible. Elsewhere an inch or less is expected, with areas south of I-90 seeing only a dusting to a tenth or two. Snow tapers off Saturday afternoon.

Meanwhile an upper wave begins to take shape over the Pacific Northwest. This wave moves east and digs south through the day Saturday, with the surface low ejecting out of Wyoming into the central Plains. As it progresses northeast an area of strong WAA will push our highs into the 30 to 40s north of I-90, and the 40s to 50s to the south. As the system continues northeast positive vorticity advection increases and works to amplify divergence aloft. The resulting band of intensifying frontogenesis in the 700 mb layer will trigger precipitation to form along and north of Highway 14 Saturday afternoon. Precipitation may begin as snow or a wintry mix, but change to rain as it sinks south into warmer temperatures. Rain eventually transitions to a wintry mix then to all snow after midnight. As the system pivots to the southeast snow will begin to intensify. Moderate to heavy snow is possible from around midnight through Noon on Sunday. Snow gradually tapers off from west to east Sunday afternoon, pushing east of the region Sunday evening. Total snowfall remains uncertain. As mentioned in a prior update, the track of the storm has shifted slightly north with the past couple of model runs, but has held steady with the 12Z run today. If the northward shift continues snow totals will come down a little more. However, if the model trends of the past few years holds, there will be another shift southward in track at 24-36 hours out. While I have adjusted totals for the current model run, I kept them minimal.

There are several threats we need to take into consideration Saturday night and Sunday. First, portions of northwest Iowa and southwestern Minnesota may see a light glaze to a few hundredths of ice accumulation before the transition to all snow.

Second, winds will become northerly behind the front. Strong CAA in the 925-850 mb layer will result in rapidly increasing, strong wind gusts Sunday. After collaboration with neighbors, have boosted winds with a 66% NBM and 33% NBM90 blend. Gusts of 45-55 mph are expected with occasional gusts to 60 mph possible. This will result in blowing and drifting snow. Visibility may decrease to less than 1/4 of a mile at times, and travel may become difficult to impossible due to blowing and drifting snow. Near blizzard to blizzard conditions are expected for portions of east central South Dakota and southwestern Minnesota. Considering the risks for ice and snow, a Winter Weather Advisory is in effect from 7 pm Saturday until 7 am Monday. Due to remaining uncertainty in track have foregone a blizzard warning at this time, however an upgrade will likely be necessary. If you have travel plans this weekend, please ensure you have an alternative in mind and that your vehicle is prepared for winter travel.

Third, wind chills will be very cold Monday morning, falling to minus 20 to minus 25. Wind chills will improve during the day but will remain near to sub-zero through Tuesday morning.

Monday will be dry but cold, with highs around 10-20 degrees F. Monday night lows will fall to the single digits either side of zero. Chances for snow return Tuesday afternoon, but are expected to be light. Highs will be slightly warmer, in the 30s to 40s with the warmest temperatures over south central South Dakota. The remainder of the week should be dry with a nice warming trend into the 40s and 50s Wednesday and Thursday, and 50s to 60s Friday.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 648 PM CDT Fri Mar 13 2026

Light radar returns are moving across the Missouri River Valley to start the period, but most of this outside of K9V9 is not reaching the ground due to dry air in the low-levels. A band of light snow will move into the area from central South Dakota and lift northward through the overnight hours, resulting in MVFR to locally IFR visibilities at times through the early morning hours Saturday. This band of snow lifts north of Highway 14 through the mid morning hours and leads to dry conditions across the area for the remainder of this TAF period. Winds will be mainly out of the east-southeast tonight into the day tomorrow, with winds picking up through the day Saturday with gusts to 25 kts by Saturday afternoon.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Winter Storm Watch from late Saturday night through Monday morning for SDZ062-066>071. Winter Storm Watch from Saturday evening through Monday morning for SDZ040-056. Winter Storm Watch from Saturday evening through late Sunday night for SDZ038-039-050-052>055-057>061-063>065. MN...Winter Storm Watch from late Saturday night through Monday morning for MNZ098. Winter Storm Watch from Saturday evening through Monday morning for MNZ071-072-080-081-089-090-097. IA...Winter Storm Watch from late Saturday night through Monday morning for IAZ001>003-012>014-020>022-031-032. NE...Winter Storm Watch from late Saturday night through Monday morning for NEZ013-014.