textproduct: Sioux Falls

KEY MESSAGES

- Severe weather risk has come to an end this evening. Rain chances end from west to east through the late evening hours.

- Clearing skies with decreasing winds will lead to some fog development into early Thursday, especially near and west of Interstate 29. Visibility may fall below a mile (20-50% chance). Fog dissipates by mid morning.

- Rain chances with some isolated thunderstorms return early Friday morning and continue through Saturday and again early next week.

UPDATE

Issued at 631 PM CDT Wed Oct 28 2026

Severe weather risk has come to an end as the initial cold front and area of convergence has moved to the east of the forecast area. Stratus is clearing behind the secondary front/CAA and as surface high pressure moves into western SD. Expect some showers/drizzle as the stratus tracks east and clears through the late evening hours and early overnight. Fog is expected to develop as winds become light, with some low to moderate (20-50%) chances of visibility below one mile into Thursday morning. Greatest risks for fog remain near and west of I-29, with most guidance highlighting the James River Valley in particular. Lows tonight may fall into the lower 30s west of the James, with 30s to lower 40s elsewhere. Fog lifts by mid morning, with a pleasant day on tap for Thursday in the mid 50s to mid 60s.

No adjustments to the forecast outside of this evening/tonight. Rain chances return with some isolated thunderstorms possible Friday into Saturday.

DISCUSSION

Issued at 131 PM CDT Wed Oct 28 2026

Over the next couple of hours, showers and storms are expected to develop over parts of eastern South Dakota and western Minnesota ahead of a cold front. Cannot entirely rule out the possibility of strong to severe thunderstorms, although the best environment will be to the northeast further into Minnesota. Still, a Marginal Risk clips the northeastern-most part of the forecast area, and hail is the main potential severe threat. Strong storms that do develop in that area are expected to exit the forecast area fairly quickly this afternoon. Further south, expectations are that showers will remain fairly light, and just a few hundredths of rain will fall.

Behind the cold frontal passage, a high pressure center will move into the area overnight tonight. After an initial shift to the northwest, winds will become light and variable overnight tonight as the high pressure center moves overhead. There is some signal in high-resolution guidance for some fog development once again tonight due to the light winds and clear skies promoting strong radiative cooling. The main area of concern for fog development is over southeastern South Dakota, particularly the James River Valley. Confidence in the areal coverage is still somewhat low at the moment, but pockets of dense fog may reduce visibility below a mile at times.

The next chances for rain come on Friday into Saturday. Rainfall will move in from the south beginning Friday before expanding to cover the entire forecast area Friday night into Saturday. Generally light rain rates are expected, but perhaps a quarter of an inch or more (20-40%) could fall over parts of northwestern Iowa, northeastern Nebraska, and southwestern South Dakota.

Another low pressure system is set to move into the region early next week, bringing renewed chances for rain into the region. Monday through early Wednesday, chances are fairly high (50-70%, increasing moving from north to south across the forecast area) to see an inch of rainfall accumulation or more. However, there is still significant uncertainty with this system in timing, location, and amounts. 25th/75th spread is generally around two inches for that same time period, so still a lot to resolve as the system comes into focus over the next couple of days.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 631 PM CDT Wed Oct 28 2026

MVFR/IFR stratus (isolated LIFR) and rain showers/drizzle continue to move east through the late evening and early overnight hours. Behind this, clear skies prevail. With clearing skies and decreasing winds overnight, MVFR to IFR fog is expected to develop into Thursday morning. Greatest risk is near and west of I-29, and especially in the James River Valley. May see visibility drop below 1SM (20-50% chances). May also see some ceilings below 1kft if the fog is a thicker layer or stratus develops.

Conditions improve by mid Thursday morning, with VFR conditions through the rest of the period. Southeasterly winds prevail around 10 knots or so, with gusts around 20 knots during the afternoon in south central SD.

FSD WATCHES/WARNINGS/ADVISORIES

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