textproduct: Sioux Falls

KEY MESSAGES

- Precipitation chances return today along and east of a Tyndall to Marshall line. Expect rain changing to snow with a brief period of wintry mix possible. Light accumulations expected. Some wintry impacts to the evening commute along and east of Iowa/Minnesota Highway 60.

- Colder temperatures return for the weekend. Isolated to scattered light snow is possible Friday and Saturday. - Warmer weather returns early to mid next week along with periodic low precipitation chances.

DISCUSSION

Issued at 310 AM CST Thu Jan 8 2026

THROUGH TONIGHT: Starting off this morning with a pretty wide range of temperatures - in the 40s still where southerly flow and clouds are keeping things mild and in the 20s where we've seen clear skies and northerly flow. Highs today in the mid 30s to mid 40s, and lows tonight in the 20s.

Change is on the way as southern stream wave moves north and northern stream trough swings through the northern Plains. At the surface, low pressure slides north from KS into IA. Expect precip to move northeast through the day and tonight, focused along and southeast of a Tyndall to Sioux Falls to Marshall line. Guidance, mainly the 08.00z NAM and associated CAMs, are showing a secondary band of precipitation which runs from Yankton to Sioux Falls to Marshall. This looks to be driven by a band of f-gen and steeper lapse rates between 850:700 mb and 700 mb vorticity near the elevated front. Biggest question will be how much low level saturation this forcing has to work with and how quickly. Onset of western slight chance pops may be a bit quick, based on some of the soundings but will have to wait and see. Expect the northern band to be short lived as the primary deformation band strengthens over northeastern NE and northwestern IA into central MN into the early afternoon and evening.

In addition to the questions about how quickly we saturate, especially the stubborn dry layer below 700 mb, there are still some lingering p-type questions. Guidance overall came in a touch warmer, keeping the rain a little bit longer in portions of the area. Still can't rule out some freezing rain/sleet especially across southwestern MN; however, soundings from multiple models show that the column cools quickly, with most seeing surface T and wet bulbs still above freezing briefly after the rest of the column cools, before cooling the surface leading to a relatively quick switch from rain to snow. Majority of soundings that keep any sort of warm nose are fall into a couple of camps: too dry for precip or sfc temp above freezing with wet bulb right at freezing. If there is a period of freezing rain or mix, expect it to remain brief (a couple hours or less).

With the slightly warmer temperatures, snowfall amounts have trended down again. An inch or less of snow is expected, with the highest totals along/east of an Ida Grove to Windom line. Since changeover should be quick, not expecting much - if any - ice accumulations. Some locations may see a light glaze. Amounts could trend back up if we cool more quickly than current guidance suggests, but still not expecting much (less than 10% of exceeding 2 inches in our far east). Impacts are expected to be minor, but areas along and east of the IA/MN Hwy 60 corridor could see wintry weather impact the evening commute.

FRIDAY-SATURDAY: Guidance has trended a little bit faster with the upper level trough axis and next mid level trough, now pushing the leading edge of the wave into the western portions of the forecast area by Friday evening. Ahead of this, 700 mb trough moves through with some CAA during the day. We'll be fighting a lot of dry lower level air Friday, so despite increasing pops from the NBM, did not add any QPF. Best chances for any measurable snow look to be along and north of US Hwy 14 on Friday, and east of I-29 on Saturday as the trough moves east. May again see some wrap around snow showers Saturday and Saturday night with continued vorticity advection and the upper level jet streak overhead. Main question during this time will be how much moisture there is to work with.

Temperature wise, Friday looks to be the warmer of the two days as the coldest air aloft doesn't get into the Plains until Friday night and Saturday. Highs Saturday in the 20s, near seasonal averages with a colder night in the single digits and teens Saturday night.

Slightly breezy winds on Friday with stronger northwesterly winds Saturday. Saturday could see gusts up to 35 mph, strongest over south central SD. This is offset from where the heaviest snow accumulations are expected earlier in the week; however, stronger winds would reduce visibility in any falling snow and could lead to patchy blowing/drifting of any fluffier snow that falls Friday/Saturday.

SUNDAY-WEDNESDAY: Trough axis moves to the east by early Sunday, leaving surface high pressure and northwesterly flow in its wake. Periodic mid level waves swing through the synoptic pattern. This may lead to periods of light precipitation, although guidance varies on moisture availability and timing/track of the individual waves. Ensemble probability of more than a tenth of an inch of 24 hr QPF during this time are less than 20%. Near to above average temperatures continue with occasional breezy days.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 527 AM CST Thu Jan 8 2026

VFR conditions to start the period. Precipitation, initially as rain, lifts north through the morning and this afternoon, focused along and east of a KONL to KMML line. Precipitation moves east through the evening, switching to snow as temperatures fall. As we transition to wet snow, may see a brief period of freezing rain and/or sleet. MVFR conditions move in with heavier precipitation and as snow mixes in. Greatest confidence in MVFR conditions is across northwestern IA into adjacent areas of southwestern MN after fully changing to snow. Minor snow accumulations are expected with up to a light glaze of ice. Precipitation moves east of the area late tonight into early Friday morning.

Outside of precipitation chances, winds shift direction this morning, becoming northwesterly. Gusts around 20 to 25 knots will be common, tapering down into tonight.

FSD WATCHES/WARNINGS/ADVISORIES

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