textproduct: Sioux Falls

KEY MESSAGES

- An active week of weather ahead, with rain and snow chances returning Tuesday night into Wednesday. Snow amounts expected to remain light (1" or less) with temperatures near freezing.

- Fire weather concerns return Thursday afternoon with strong winds and lowering humidity.

- Rain and snow chances move in Thursday night and Friday with low precipitation amounts expected once again.

- All interested parties should begin to monitor a storm system for next weekend. Higher than normal agreement in model guidance suggests a large storm in the Northern Plains that may impact travel.

UPDATE

Issued at 1124 PM CDT Mon Mar 9 2026

Tuesday morning an area of light drizzle to flurries is possible over east central South Dakota and southwestern Minnesota. These will have to fight through some dry air closer to the surface and so meaningful accumulation is not expected. Highs will be limited due to increasing clouds through the day, looking to reach the mid 40s north of I-90 and the low to mid 50s to the south. By the afternoon precipitation chances increase for the region.

Tuesday morning an area of positive vorticity advection over southeastern Montana will work to increase mid-level frontogenesis. This band of vorticity is in association with the deepening shortwave over the northern Rockies. This wave will continue to dig to the south and move east through the day, creating light precipitation as it does so. The overall track of the system is in good agreement across guidance, as well as the onset timing of precipitation. Guidance has precipitation entering our northwestern corner by the early afternoon. Initially the band of precipitation will have a west to east orientation. As we head into the evening the wave takes a sharp turn to the southeast, turning the band into a southwest to northeast orientation. As far as totals, QPF for this system has overall trended down with the latest short term guidance. A trend that the NBM has picked up on. QPF looks to be limited to a few hundredths of an inch for the majority of the region, and a tenth or two for portions of southwestern Minnesota. This is due to a cold front stretching from south central Kansas through Missouri and into southeastern Iowa that will work to block moisture moving north from the Gulf region. Precipitation is most likely to start as rain, but as temperatures rapidly fall after dark a quick transition to snow is expected. Snow totals for most of the region will be less than an inch, with southwestern Minnesota seeing isolated higher totals of 1.5 to 2 inches. Snow should be east of the region by mid to late morning Wednesday. Overnight lows will fall to the 20s and low 30s.

Wednesday will be cooler thanks to northwesterly winds, highs are expected to climb into the 40s. CAMs indicate late Wednesday afternoon a band of light rain is possible. Soundings indicate a sporadically saturated layer through the DGZ with weak instability. However, any showers would need to overcome a dry surface layer. The more likely scenario is this layer will produce some mid-level clouds and possibly virga.

The remainder of the forecast remains on track for the latter half of the week. Thursday the main concern remains the hot, dry, and windy conditions resulting in High to Very High Grassland Fire Danger. Friday into the weekend looks at a pattern change that brings more chances for light precipitation and colder weather. Please see the discussion below for more details.

DISCUSSION

Issued at 1213 PM CDT Mon Mar 9 2026

THIS Afternoon: A backdoor cold front has pushed through the area this afternoon, slowing the warming of temperatures in area along and north of I-90. The residual warm air aloft and modest mixing will still allow high temperatures to push into the 50s and 60s.

TONIGHT: Northerly winds continue tonight, actually increasing in gust potential after dark as mid-lvl vorticity passes to the north. That said, low temperatures will struggle to fall through the 40s and into the 30s as mid and upper cloud cover increases through the night.

TUESDAY: Sloped mid-lvl frontogenesis increases along the SD/ND border early on Tuesday in response to the arrival of a mid-lvl area of vorticity crossing the Northern Rockies. This initially E-W band of precipitation will begin to shift southeast late in the afternoon as the wave approaches. Some higher resolution guidance also shows lower level frontogenesis closer to I-90 in the morning that could develop high based virga/sprinkles trailing from central MN southwest into eastern South Dakota. Northeasterly wind and increased cloud cover will hold down temperatures slightly, with highs only in the 40s to 50 in the afternoon.

TUESDAY NIGHT: Precipitation will move from NW to SE through the evening and overnight hours, with light rain/snow mixture turning to snow as deeper cold air aloft sinks southward. Moisture will remain limited with this system, with no direct feed from the Gulf as convection along a cold front in MO/KS develops and interrupts flow. The end result will be low QPF totals with the probability of >0.10" around 40% in LREF guidance. Some higher resolution guidance does show QPF totals as high as 0.15" (around 75th percentile of HREF), with HREF probabilities of >0.10" over 60% along a focused area from Marshall to Sioux Falls to Le Mars to Windom. With marginal surface temperatures near freezing, snowfall totals will also remain light with a dusting to 1.5" possible by time precipitation exits to the east at daybreak. Have adjusted SLR and changeover temp slightly to bring more snow in than rain during the bottom of the diurnal temperature curve overnight.

WEDNESDAY: A broad mid-lvl trough passing through the region on Wednesday will keep temperatures cooler, but still above normal. Northwest winds prevail, with guidance showing the potential for very light QPF tied to weak mid-lvl warm advection sliding through the region in the afternoon. The spatial variance in QPF in model data is suggestive of broad but low PoPs potential and will be refined closer to the development timeframe. Temperatures remain in the 40s.

THURSDAY: Mid-lvl heights rise Thursday in response to a building ridge of the West Coast and upper trough moving through the Canadian Rockies. The rapid deepening of surface cyclogenesis over Montana and North Dakota will spur an intense SPG further south, drawing warm and gusty southwest winds into the Dakotas. With high temperatures surging into the 60s, we'll need to take a careful look at RH and winds in the afternoon. Soundings would suggest that the deterministic NBM wind gusts of 26-30 knots (near the 50th percentile) may end up being too low, with the 75th percentile guidance favored. This would result in wind gust closer to 35-40 mph at times in the afternoon. NBM dew points in the upper 20s to lower 30s are sitting near the 75th percentile of the NBM, and have favored lower values based on synoptic setup. The fly in the ointment will be the positioning of the elevated and surface warm front which could draw in both cloud cover and even scattered showers to the north of where the boundary forms. Currently, this could be positioned near the I-90 corridor, pushing the greatest fire danger concerns to areas in the south.

FRIDAY: Light rain moves through areas along and north of this aforementioned boundary into Friday morning, with light QPF amounts once again favored. High pressure then arrives for most of the daytime hours of friday favoring a drop in highs back to the lower 40s to near 50 degrees.

SATURDAY-MONDAY: "Beware the ides of March" may once again prove true next weekend as we're keeping a close eye on the potential for a larger storm system moving into the Plains. Medium range models are in stronger than normal agreement pulling a progressive upper trough out of the North Pacific and across the Rockies and into the Plains by Saturday. Behind this trough a 160 knot upper jet will help deepen this wave as it crosses the Plains, to what degree is the biggest question of the extended forecast. LREF guidance and their incorporated ensembles suggest a higher than normal confidence forecast with nearly all ensembles indicating a >60% probability of >0.10" of precipitation into Sunday. Some spacial agreement also persists in higher totals >0.50" with focus along and north of I-90. Obviously a LOT can change over the upcoming days, but given the potential combination of snow and wind this system could bring to areas of SD/MN, it's not a bad idea to begin monitoring if there are regional travel plans this weekend.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 635 PM CDT Mon Mar 9 2026

VFR ceilings and visibility expected to prevail through the period. Northeasterly winds are expected to gradually increase through the evening as a surface low pressure sinks southeastward from Wyoming. Gusts will increase to 20-25 kts by very early Tuesday morning for areas north of I-90 and west of I-29. Stronger winds gradually progress southeast through the rest of the night, decreasing to 15- 20 kts shortly after sunrise. Winds will then remain somewhat steady through the end of the period.

Mostly clear skies will fill in with mid to high level clouds about the same time the winds are expected to increase. Weak lift through the cloud layer may produce some light sprinkles to snow flurries, but very little is expected to reach the ground through the subcloud dry layer. Near the end of the period ceilings are expected to begin to lower ahead of an incoming wave Tuesday evening.

FSD WATCHES/WARNINGS/ADVISORIES

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