textproduct: Sioux Falls

KEY MESSAGES

- Today will be the final day of near-record to record temperatures, with record highs more likely south of I-90.

- High to Very High grassland fire danger are expected today and Wednesday as stronger winds return.

- Cold front may trigger showers and isolated thunderstorms late this afternoon and evening. Severe weather is not expected, but showers/storms may contain isolated stronger gusts up to 50 MPH.

- Snow potential is growing late this week, especially Thursday into early Friday. Moderate (40-70%) probability of minor impacts with snowfall exceeding 1-2 inches and patchy blowing snow. Low (10-30%) probability of moderate impacts.

UPDATE

Issued at 310 AM CST Tue Feb 17 2026

Quiet weather early this morning, but that looks to change through the remainder of the work week as we transition from Spring back to Winter.

Today will see mild morning temperatures warm into the 60s to lower 70s. With existing records several degrees higher than yesterday, the greatest chance for additional record highs will be in areas south of I-90. Unlike our previous very warm days, increasing southeast flow will bring higher dew points into the region (widespread 40s by this afternoon), which should help to keep fire weather concerns below critical levels. However, the increase in low level moisture will support an increase in elevated instability by late afternoon and evening. At the same time, a developing low level jet will impinge on a cold front swinging through the area. This will bring not only a chance for scattered high-based showers, but perhaps a few thunderstorms as well. Severe weather risks are low, but with the increasing low level jet and inverted-V look to the soundings due to very dry sub-cloud air below 700mb, could see isolated stronger wind gusts to around 50 MPH.

More notable will be the potential for broader mixing of strong westerly winds aloft to the surface in the push of post-frontal cold advection and have nudged NBM winds upward by blending in some 90th percentile along with the HRRR/ARW. This leads to advisory level winds for the northwest quadrant of the forecast area late tonight into Monday morning and have issued a Wind Advisory for areas generally along/north of I-90, and along/west of I-29 for Midnight-Noon Wednesday.

The strongest winds begin to diminish Wednesday afternoon as cold advection weakens and a surface ridge begins to work into the southwest half of the forecast area. This could be enough to keep us below critical fire weather conditions on Wednesday, but this will have to be monitored as even with weakening winds, the relative humidity levels will be rather low (15-30%), especially along and south of I-90.

That will be our last taste of Spring, as our late week system is coming into better agreement. Appears to be not quite as strong as the EC and its ensembles had been projecting, but still a somewhat slower wave that will impact the region Thursday into Friday. The trends lend toward slightly higher confidence in snowfall, with moderate to high (50-70+%) potential for shovelable snowfall exceeding an inch or two, and low-moderate (30-50%) probability of topping 4 inches, highest toward south central South Dakota. These amounts along with breezier north winds will bring the potential for areas of blowing snow as well, so those with travel plans Thursday into Friday will want to monitor the latest forecasts.

DISCUSSION

Issued at 231 PM CST Mon Feb 16 2026

It's been another warm and pleasant mid-February day out there! Clouds will increase through tonight as our next storm system approaches the area, and this will prevent any fog from developing like we saw earlier this morning. It will also mean a warm night is ahead, with temperatures only dropping to the mid-30s to low-40s by daybreak tomorrow. A trough will eject out of the northern Rockies as a surface low over the northern Plains deepens. We'll remain on the warm side of the system, so any precipitation that falls during the day on tomorrow will be in the form of liquid. Guidance shows some light rain moving through the area tomorrow morning, but ample dry air in the sub-cloud layer will prevent most of this from reaching the ground. Still, a few sprinkles cannot be ruled out tomorrow morning.

As we head into tomorrow afternoon and evening, the cold front associated with this system will move through the area and provide some lift for some showers to develop. The best chance of this occurring will be along and east of I-29, and these showers will move into an environment characterized by 200-500 J/kg of MUCAPE, so a few rumbles of thunder cannot be ruled out. Some wrap-around moisture from this system may clip mainly the Highway-14 corridor (20-40% chance) tomorrow night into Wednesday. As temperatures cool behind the front, some of this may fall as a few snowflakes, but impacts are not expected. Winds will become breezy once again on Tuesday as this system deepens over the area, but more on how these winds and how this will affect our fire weather threat tomorrow and again on Wednesday will be discussed in the Fire Weather Section later on in this discussion.

Attention turns to our next storm system moving in Thursday into Thursday night. Fairly good agreement amongst guidance that a low pressure system will drift across the central Plains, with the EC showing the system closing off closer to our area while other deterministic models have this moving through our area as an open wave and then closing off to our east over eastern Iowa. Another piece of uncertainty will come from where the system tracks, with the NAM keeping most of the precipitation south of the area, while most guidance gives our area at least some precipitation. Colder temperatures should be in place by the time this system moves through, so any precipitation would likely fall as snow. In terms of amounts, guidance varies with anywhere between a dusting and a few inches of snow. With so much uncertainty on the track and development of this system, we'll need to look at snowfall total probabilities to give us an idea of how much snow we may see out of this system. The EC ensemble is leading the way with snowfall chances, which shows a broad 50-80% chance of at least an inch of snow and a 25-55% chance of at least 4 inches. Other ensembles are lower, with a 30-50% chance of at least an inch of snow and then dropping off to a less than 15% chance of at least 4 inches of snow. The EC continues to remain an outlier, and with the progressive nature of this system that most guidance shows, would tend to lean towards these lower probabilities at this time. However, light snow and breezy conditions on Thursday into Thursday night could lead to some minor travel impacts no matter how much fall, so please keep up to date with the latest forecast.

Temperature-wise into this weekend, the NBM is showing seasonal temperatures, though this will be ultimately affected by how much snow falls, if any, on Thursday/Thursday night. More snow would mean colder temperatures this weekend, with less snow meaning seasonal or even slightly warmer temperatures.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 543 AM CST Tue Feb 17 2026

Patchy MVFR fog possible east of the Buffalo Ridge in southwest Minnesota early this morning. Otherwise VFR conditions should be prevalent through the TAF period.

Southeast winds increase this morning, with frequent gusts 25-30kt through the afternoon. A cold front sliding east across the region this evening will trigger high-based showers and perhaps a few thunderstorms. Potential for thunder is too low to include in TAFs at this time. Any showers/storms may produce brief erratic wind gusts in excess of 40kt. Behind the cold front, west winds increase further after 06Z with gusts 25-40kt becoming more widespread late in this TAF period. Strongest wind gusts are expected north of I-90 corridor.

FIRE WEATHER

Issued at 543 AM CST Tue Feb 17 2026

Increasing southeast winds gusting 25 to 35 mph this afternoon will result in High to Very High grassland fire danger. With temperatures rising into the 60s to lower 70s this afternoon, we are looking at relative humidity as low as 20 to 30 percent along the Missouri River Valley. However, these lowest humidity levels should be displaced from the stronger gusts, which will be focused along/northeast of a line from Huron to Sioux Falls to Spencer Iowa. As such, fire weather conditions are expected to remain below critical levels today.

Stronger west winds across the area Wednesday morning are forecast to diminish through the afternoon. A drier air mass combined with the gusty winds will still result in Very High fire danger across the region. Locally critical conditions are possible, so be sure to monitor conditions.

CLIMATE

Issued at 315 PM CST Tue Feb 17 2026

Today will be the last day of near-record to record highs with a potential for near record warm low temperatures as well:

Record high temperatures:

February 17: KFSD: 70/1981 KSUX: 71/1981 KHON: 67/1913 KMHE:70/1913

Record warm low temperatures:

February 17: KFSD: 33/1992 KSUX: 37/1930 KHON: 35/1981 February 18: KFSD: 38/1994 KSUX: 39/1971 KHON: 35/1994

Additionally, climate perspectives indicate that the current forecast through Wednesday the 18th would push the mean monthly temperature departure at Sioux Falls (+16 degrees), Sioux City (+16 degrees), and Huron (+18 degrees) as the warmest February on record through that date by a margin of nearly a full degree.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Wind Advisory from midnight tonight to noon CST Wednesday for SDZ038>040-052>061. MN...Wind Advisory from midnight tonight to noon CST Wednesday for MNZ071. IA...None. NE...None.