textproduct: Sioux Falls

KEY MESSAGES

- A few stronger storms will be possible Saturday afternoon into late Saturday evening, with hail and lightning as the main concerns.

- Sunday is very warm and a bit breezy with drier air moving in especially into central South Dakota. This will lead to elevated fire weather concerns Sunday afternoon mainly for areas west of I-29.

- A better chance for stronger storms arrive Monday and possibly again on Tuesday. The better chance for these stronger storms are currently favoring areas east of the James River on Monday and then for portions of northwest Iowa on Tuesday.

UPDATE

Issued at 850 PM CDT Thu Apr 9 2026

Taking a look across the area, the precipitation shield continues to progress eastwards this evening promoting periods of drizzle, rain, and snow along and east of I-29 depending on surface temperatures. With a clearing starting to take shape west of Highway-81, current estimations are around the 9-11 pm timeframe that most areas should become clear with a surface high approaches from the northwest. From here, continued the trend of lowering our temperatures for tonight especially across our northwestern-most zones by blending in some of the Canadian into the forecast. This resulted in temperatures in the 20s for most areas with increasing potential for a few upper teens near Huron and De Smet. Quieter conditions will return for most of Friday with highs returning to the mid 50s to low 60s. Lastly, should see cloud cover gradually increase from west to east from Friday night into Saturday as warm air advection (WAA) strengthens.

Looking into Saturday, we're still on track for two rounds of showers and potentially thunderstorms. The first of which should arrive by Saturday morning as bits of isentropic lift with an approaching shortwave interact with a strengthening LLJ (40-50 kts) in the WWA regime. This will likely lead to scattered showers developing from around daybreak through late morning. After this activity progresses eastwards, lingering stratus (lower clouds) from the morning activity could potentially diminish our chances for thunderstorms in the evening as the atmosphere stabilizes. The chances aren't exactly zero though. A strong LLJ and lifting shortwave should usher in any developing activity from eastern NE into eastern SD and western/central IA during the evening hours. However, with weakening instability and shear with northeastward extent; not sure if any developing thunderstorms will survive the journey. Nonetheless, could still see pockets of light to moderate rain along and east of I-29 into Saturday night.

DISCUSSION

Issued at 227 PM CDT Thu Apr 9 2026

We've seen some widely scattered showers moving across the area today, and this will continue to be the case through the early evening. Some snow or sleet may mix in north of I-90 late this afternoon/early this evening as we wet bulb down, but impacts are not expected outside of wet roads given above freezing ground temperatures. Additionally, an isolated thunderstorm cannot be ruled out over northwest Iowa during the remainder of the afternoon, but severe weather is not expected. High pressure moves across the area tonight as clouds and precipitation move off to our east. Areas that saw precipitation today could see some light fog develop as winds turn light to calm and skies clear out. Look for lows tonight in the 20s across the area, though can't rule out some spots along Highway 14 especially east of I-29 dropping into the upper teens given skies will clear there first overnight.

Quiet weather expected for Friday and it will also be warmer with highs in the mid to upper 50s across the area. Warm air advection increases Friday night, which could result in widely scattered showers heading into daybreak Saturday. As we continue to pull in moisture into the day on Saturday, additional showers and even a few thunderstorms look to develop as daytime heating occurs. Instability looks limited during the daytime hours on Saturday; however as we head into the evening, the low level jet (LLJ) looks to strengthen and will help funnel in warmer and more humid air. This could lead to around 1000 J/kg of MLCAPE and thus an isolated stronger storm with some hail is possible Saturday evening; so this will be something to keep an eye on. With all this southerly flow in place, look for highs in the 60s and 70s on Saturday, warmest in south-central South Dakota. Saturday also looks to be breezy with gusts to 35 mph; however with the surge of moisture expected within the southerly flow, relative humidity values look to be well above critical levels.

A negatively tilted trough ejects across the northern Plains on Sunday, with a surface low developing across the Red River Valley. At this point we could get some showers and an isolated storm from this mainly east of I-29, though it looks like precipitation won't become more widespread until after this system passes us to the east. With that said, it will allow for us to be in west- southwesterly flow through the day on Sunday. This will mean a very warm day with drier air moving in. Look for highs in the upper 70s to mid 80s with relative humidity values dropping into the 20-30% range west of I-29. Winds won't be as strong as Saturday, but it still looks breezy with gusts to around 30 mph possible. This means Sunday will be a day to watch for elevated to potentially critical fire weather concerns.

A deep upper trough hanging out near the Pacific Coast will finally begin to move eastward heading into early next week, keeping inclement weather in the forecast for Monday and Tuesday. The eastern half of the area is currently highlighted in a 15% risk for severe weather by the Storm Prediction Center, and then we are just outside a 15% risk to our southeast for Tuesday. The upper level support will certainly be there with the aforementioned trough expected to eject across the area, so it will be up to the finer mesoscale details before the exact severe threats (wind, hail, etc.) can be determined. Ensemble probabilities of surface CAPE greater than 1000 J/kg for areas east of the James River ranges from 40-70% chance according to the NBM and the Canadian ensemble to a 20-50% chance according to the GEFS Monday afternoon. These higher probabilities shift farther south and east for Tuesday afternoon, but still include portions of northwest Iowa. Be sure to keep up to date with the latest forecast!

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 615 PM CDT Thu Apr 9 2026

Mostly VFR conditions will persist this TAF period. Taking a look at satellite imagery, a VFR stratus/altostratus deck continues to progress through the area this afternoon. While this deck does continue to produce intermittent pockets of drizzle, rain, and the occasional ice pellet, should see things continue to progress eastwards into the evening with minimal aviation concerns. From here, northeasterly winds will become more light and variable by late evening as a surface high progresses through the area to end the TAF period.

FSD WATCHES/WARNINGS/ADVISORIES

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