textproduct: Sioux Falls

KEY MESSAGES

- Periods of scattered showers with isolated thunderstorms will return by Saturday with mostly light accumulations expected.

- Elevated to potentially critical fire concerns are expected by Sunday as unseasonable warmth returns along with breezy westerly winds. This along with critical RH values (18%-30%) will lead to high to very high fire danger with the focus being west of I-29.

- Renewed chances for showers and storms return on Monday and Tuesday with the potential for a few stronger storms. However, some details remain uncertain.

UPDATE

Issued at 1054 PM CDT Fri Apr 10 2026

Looking across the area, we're starting to see cloud cover increase from southwest to northeast this evening as warm air advection (WAA) strengthens this evening. Expect cloud cover to eventually blanket the area overnight as our precipitation chances increases near daybreak on Saturday. Overall our rain chances remain on track for the morning hours with most areas east of the James River Valley likely seeing scattered showers. While mostly light accumulations are expected, some areas east of I-29 could see slightly higher amounts as pockets of moderate to heavy develop with some activity. From here, should see most of this activity gradually progress out of the area by early afternoon on Saturday leaving behind mainly a lower cloud deck (1kft or less).

With this in place at least through Sunday morning, confidence has significantly decreased in our overall severe weather risk for the evening hours. However, with lingering low-level moisture expected according to soundings; there now is increasing potential for areas of drizzle through Sunday morning mainly east of Highway-81. As a result, decided to decrease overall POPs after 21z (4pm) only keeping drizzle in through Sunday morning. Looking ahead, Sunday continues to look like a picture perfect fire weather day with critical RH values (18%-30%) and breezy westerly winds (25-35 mph gusts). This combined with temperatures in the low to upper 80s will lead to high to very high fire danger with the focus being across southcentral and southeastern SD.

DISCUSSION

Issued at 230 PM CDT Fri Apr 10 2026

It's a fairly pleasant and sunny Friday afternoon across the area! Changes are on the way though; it will get warmer... but also a bit stormier. Warm air advection (WAA) increases tonight, helping to bring some showers into the area early Saturday morning. These showers will move into the Missouri River Valley at first and lift northeastward into Saturday morning. A few rumbles of thunder will be possible with this activity, but severe weather is not expected. With the return of southerly flow and cloud cover associated with the aforementioned showers, expect a much milder night tonight with lows in the upper 30s to low 40s.

Warm air advection showers will be ongoing Saturday morning especially east of I-29. These showers will push off to our east into north central Iowa and south central Minnesota through the early afternoon. Saturday will be warmer and breezy, but with showers around and increasing moisture due to continued southerly flow, the fire weather danger will be low. The only place where we could see elevated fire weather concerns Saturday afternoon would be over south central South Dakota where clouds decrease the quickest and thus it will be a bit warmer out that way. Off to our west, an upper wave will be moving across the Rockies and sending impulses our way. Additional showers and storms may develop overnight Saturday into Sunday as the low level jet strengthens, allowing for around 1000-1500 J/kg of instability to move across the area. Any storms will be elevated given the capped low levels, leading to large hail up to the size of quarters as the main threat if a storm can become severe. The better chances of an isolated severe storm will be over northwest Iowa early Sunday morning, right where the Storm Prediction has the area in a Level 1 out of 5 Marginal risk for severe weather.

A shortwave trough will move across the northern Plains on Sunday and in response, a low pressure system will move across the Red River Valley into southern Canada. West-southewesterly flow will return to area in the wake of this system and bring a punch of much drier air into the area, especially west of I-29. This is where relative humidity (RH) values will drop below 30%, with RH values as low as 18-20% possible in south central South Dakota. It will be breezy and warm, with wind gusts around 30 mph and highs into the 80s. All this will lead to elevated to potentially critical fire weather concerns for areas west of I-29, so Sunday will be a day to avoid outdoor burning. Winds look to decrease through the late afternoon, so this could limit the extent of the fire weather threat into Sunday evening, but keep in mind it will still be dry and warm.

The active weather pattern continues into Monday as a deep trough over the central West Coast begins to move eastward. Monday looks to have the better chances for severe weather compared to Sunday morning, though uncertainty remains especially with the location of storm development. The 10.12Z ECMWF has storms developing over our area, while the 10.12Z runs of the NAM and RRFS have storms not developing until east of the area. This is at least in part due to timing and placement differences in the position of a surface low, with the ECMWF slower with this and the NAM and RRFS being faster. These finer details will need to be ironed out before we could start looking into individual severe threats, though a slower solution would favor surface based storms while a faster solution would favor elevated thunderstorms. The parent trough will eject across the area on Tuesday, and this could potentially lead to another threat of stronger storms as yet another low pressure system moves across the region. A few showers may linger into Wednesday, but models diverge significantly from there. With no big pushes of cold air advection following any of these systems, we look to remain warm into much of next week with highs possibly staying the 70s even into Wednesday and Thursday of next week.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 640 PM CDT Fri Apr 10 2026

VFR conditions this afternoon will transition to mainly MVFR to IFR conditions and lower this TAF period mainly due to increasing precipitation chances. Cloud coverage should gradually increase after 05z (12am) with altostratus and MVFR to IFR stratus moving in from southwest to northeast. Pockets of light to moderate showers should develop in the lowering cloud base between 08z-12z (3am-7am) on Saturday. Used PROB30s at each TAF site to time in the precipitation shield before going prevailing at each site. While confidence is high in the first round of rain, still have a few questions about the second expected from Saturday night into Sunday which has lead to lower confidence. Lastly, light and variable winds this afternoon will become more southeasterly into the evening hours. Surface winds will increase overnight into Saturday becoming more breezy.

FSD WATCHES/WARNINGS/ADVISORIES

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