textproduct: Sioux Falls

KEY MESSAGES

- Rain and drizzle continue through the evening, slowly tapering off from southwest to northeast overnight.

- Low (20-30%) chances for patchy fog into Tuesday morning. Visibility may briefly decrease to 2 miles or less, with conditions improving by mid morning.

- An active pattern leads to additional rain chances on Wednesday and over the weekend. Monitor your local forecast if you have any outdoor plans.

- Near to above normal temperatures return from Wednesday onward with highs in the 60s to lower 70s.

UPDATE

Issued at 832 PM CDT Mon Oct 26 2026

No significant changes to the forecast this evening. Rain and patchy drizzle continue to lift north across the area, with clearing from southwest to northeast expected overnight as low pressure lifts north. Although temperatures are on the cooler side (upper 30s to upper 40s), we're warm enough to stay all rain here - unlike locations across western SD that have seen snow today.

Guidance still shows the potential for some fog, mainly in the valleys near and west of the James River, and across the higher elevations of the Buffalo Ridge thanks to how low the cloud bases are. Drizzle may also be more prevalent than fog, as soundings show a low but relatively deep saturated layer. Regardless, impact will be the same with reduced visibility, as or below two miles at times if fog/drizzle develops.

Dreary conditions continue into Tuesday, even after the rain comes to an end. Still looking at a cooler day as stratus lingers into the afternoon, despite increasing southerly winds and southwesterly flow aloft later in the day. Highs Tuesday in the 50s to mid 60s with wind gusts west of the James around 25 mph.

DISCUSSION

Issued at 306 PM CDT Mon Oct 26 2026

Light, periodic rain showers will continue through the remainder of this afternoon and into the overnight, gradually dissipating from southwest to northeast. A period of light drizzle is possible as moisture wraps around the low in the early morning hours of Tuesday. There is potential for fog to develop overnight along river valleys and low areas. There is approximately a 20-30% probability that visibility may briefly fall to 2 miles or less. All shower activity should be northeast of the CWA by around sunrise, and fog should burn off shortly after. Overnight lows will dip into the upper 30s to mid 40s. Thick, low stratus clouds linger into early Tuesday afternoon before being swept away by a second shortwave moving through western North Dakota. Winds become southerly and increase in response to the tightened SPG. Gusts of 20-30 mph are possible along and west of the James River Valley, with gusts generally less than 20 mph to the east. Shallow mixing will tap into strong WAA in the 925-850 mb layer. At the surface we can expect highs to warm nicely into the low 50s to low 60s. The warmest temperatures are expected over central South Dakota and northeastern Iowa.

Wednesday morning lows will be warm for late October, in the 40s to low 50s. Average lows this time of year are in the lower 30s. Another day of light to breezy southerly winds and strong WAA will warm our afternoon highs in the 60s and 70s. Similar to the lows, we are quite warm for this time of year when average highs are generally in the mid 50s. Around mid-morning a broad upper wave and weak surface low will take shape over central Canada. An associated cold front will drape from there southwest through central South Dakota into southeast Wyoming. Light rain is expected to develop along the front, mainly west of the James River late in the morning. As the wave and frontal system move southeast rain will move into the I-29 corridor and into western Minnesota and Iowa. Rain is expected to be spotty in nature with little accumulation. Only a few hundredths to a tenth or two. Showers clear out to the east after midnight. Behind the front winds become northwesterly and light. This will allow for good radiational cooling and lows will drop into the mid 30s over central South Dakota to the upper 40s east of I-29. Thursday winds aloft will become zonal to south-southwest. At the surface high pressure builds in from the northwest. Winds will turn southeasterly as that high scoots off to the east, but remain light. Dry and mostly sunny conditions with highs in the low to mid 60s. The majority of the day Friday will be dry with highs in the 60s. Friday late afternoon and into Saturday another shortwave system moves through bringing additional chances for rain. While currently rainfall looks to be spotty and light, this could impact outdoor Halloween plans. A brief break on Sunday before a much more pronounced upper trough brings wide spread chances for accumulating rainfall to the area Monday into late Tuesday. While uncertainty is very high at this juncture, long term ensemble guidance indicates the potential for widespread 0.5 to 1 inch. Stay tuned as we monitor the trends with this system and details emerge.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 633 PM CDT Mon Oct 26 2026

Rain showers have diminished over south central SD this evening, but will continue to lift north through the overnight hours, tapering off from southwest to northeast.

Main concern through the period will be the visibility restrictions (MVFR to IFR at times) for rain/drizzle and potentially some patchy overnight fog. Additionally, MVFR and IFR stratus, with patchy LIFR stratus remains in place through Tuesday morning into the afternoon, with guidance quite varied on how quickly ceilings improve. For this forecast, generally trended toward some of the more optimistic ensemble guidance for timing to upper MVFR/lower VFR ceilings Tuesday afternoon. Ceilings are also expected to improve from southwest to northeast Tuesday.

Winds will be quite varied in direction through the period, although expect some brief light and variable winds overnight into Tuesday morning. Southerly winds return later in the period, with gusts near and west of the James River 20 to 25 knots Tuesday afternoon/evening.

FSD WATCHES/WARNINGS/ADVISORIES

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