textproduct: Sioux Falls

KEY MESSAGES

- A strong cold front will arrive tonight, bringing stronger winds up to 30-40 mph overnight. Isolated gusts up to 50 mph are possible.

- Precipitation remains on track for Wednesday and Thursday. Starting to see though types and amounts remain uncertain as small changes in the systems track and structure can have meaningful changes on the forecast.

- A second system is on the table for Friday and Saturday which could bring another round of rain and snow to the area. Details with this system are much less certain.

DISCUSSION

Issued at 304 PM CDT Mon Mar 30 2026

Elevated fire danger continues this afternoon particularly south of I-90 as humidity levels have fallen to 20-30+% while winds are only elevated at 10-30 mph. These conditions persist for the rest of the afternoon hours before temperatures begin to cool this evening, ending the fire danger.Thus, have issued a Special Weather Statement (SPS) for locations along and south of I-90 through 7pm to account for the near critical fire danger. Things will change during the overnight hours as a cold front pushes through the area. This front will deliver strong winds in its wake via a stronger shot of cold air advection (CAA). Winds will turn to out of the northwest with gusts up to about 30-40 mph with isolated higher gusts up to about 50 mph. At the same time, a few isolated showers are possible. If these showers are able to develop ahead of the incoming cold front, then they could produce some gusty winds up to about 40 mph.

Winds will be weakening through the morning hours on Tuesday. With a new postfrontal airmass in place, high temperatures will be cooler, but still above average in the upper 40s to about 60F, warmest across northwest Iowa. A few stray rain showers are possible throughout the day but otherwise Tuesday will be a cloudy day. Come the afternoon hours, humidity levels look to fall to 25-40%. Despite the weakening winds, winds will still have gusts strong enough to continue elevated fire danger across the area. Things begin to change Tuesday night as heights begin to fall aloft. An upper level trough will send weak shortwaves out ahead of it, bringing a return of precipitation to the area. This precipitation will be tied to locations west of the James River for the overnight hours and may not reach the ground for much of the night until thermal profiles saturate.

Precipitation will become more widespread on Wednesday, especially the evening timeframe as better forcing for ascent arrives. This will keep high temperatures near seasonable in the upper 30s and 40s. The main uncertainty regarding precipitation type (P-type) at this time is where does the thermal gradient aloft set up. If it stays further to the south, then more snow can be expected. If it pushes northwards, then a mix of rain/snow or even mostly rain would be on the table. Latest ensembles suggest that precipitation will begin as snow before transitioning to a mix of rain and snow by the afternoon timeframe. This is supported by the Euro and AI Euro ensembles. The NBM is the coldest of these ensembles though still in line due to its relatively higher resolution. At the same time, wetbulbing could keep the p-type mostly snow though again this depends on how the thermal gradient sets up. Chances for precipitation will persist through Wednesday night. With cooling temperatures, the main p-type will transition to snow though the ensembles are picking up on the potential for some mixed precipitation, including freezing rain. This will depend on how the thermal profiles shake out but do think the warm air advection (WAA) aloft would be strong enough while ageostrophic northerlies from the right entrance region of an upper level jet may keep surface temperatures just cold enough for some freezing rain accumulation to occur. Thus, have left a light glaze of ice in the forecast, mainly for locations just east of I-29. Precipitation will persist through much of Thursday as the main wave ejects into the Upper Midwest. With the main trough axis swinging through the area by Thursday afternoon, the bulk of the remaining precipitation is expected to fall Thursday morning. Although the dendritic growth zone (DGZ) will dry out aloft, the low level look to remain saturated which could keep very light precipitation to perhaps drizzle going through the afternoon hours. Amounts are beginning to come into a better picture with what looks to be a broad 1-3 inches possible along and north of a Jackson, Minnesota to Sioux Falls, South Dakota, to Lake Andes, South Dakota line. Isolated higher amounts are possible along the Buffalo ridge due to some upslope enhancement. Thus making this a lighter snowfall but longer duration event. Given the remaining uncertainty, do want to stress that these can and will likely change over the next day or so. Please continue to monitor the latest forecast for the most up to date information.

A small break in the action is expected Thursday night before another round of precipitation break out across the region on Friday. This second round of precipitation is due to another upper level wave ejecting out of the Rocky's. Although this wave appears stronger than the first one, more uncertainty is expected with it. Integrated Vapor Transport (IVT) does not look as good with this second wave and medium range guidance shows much larger variance in the upper level pattern. The ensembles again do suggest the potential for another round of a mix of rain and snow. Amounts are also highly variable. Looking aloft, the ensembles are somewhat in agreement with each other in the structure of this upper wave. But they do differ quite a bit in its overall evolution with the GFS ensemble being the fastest with the wave while the Euro ensemble is the slowest. Too early to say anything about amounts at this time but something to continue to monitor over the coming days as chances for precipitation look to be on the table for Friday and Saturday.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 647 PM CDT Mon Mar 30 2026

The main aviation concern is increasing north winds behind a cold front which pushes south across the region tonight. Gusts 30-35kt will be most common, but could see a brief push of gusts topping 40kt. This would be short-lived and difficult to pinpoint timing, so did not include gusts above 35kt in any TAFs at this time.

VFR conditions prevail for most areas through the TAF period. The exception will be a brief period of MVFR ceilings which may impact portions of northwest Iowa including KSUX prior to sunrise.

FSD WATCHES/WARNINGS/ADVISORIES

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