textproduct: Sioux Falls

KEY MESSAGES

- Rain is likely throughout the day for most of the area to start the new work week. Amounts through tonight will range from 0.5 to 1.5". Locally higher amounts remain possible in a corridor between the James River and MN/IA Highway 60.

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

- Near to slightly above normal temperatures will return from Wednesday onwards with daily highs in the low to upper 60s with a few low 70s at times.

UPDATE

Issued at 348 AM CDT Mon Oct 26 2026

A chilly rain continues to spread into northwest Iowa, eastern South Dakota, and southwestern Minnesota early this morning. An area of rain extends southwestward into central and western Nebraska, and all this activity will gradually lift north/northeast heading into the daytime hours Monday as an upper wave ejects into the central/northern Plains. Temperature-wise, most locations are ranging from the upper 30s to middle 40s, and these temperatures will stay steady through daybreak. Make sure to grab the rain jacket and umbrella before heading to work or school this morning!

Rain is likely across most of the area throughout the entire day today, the exception will be over portions of northwest Iowa mainly near and southeast of a Spencer to Sioux City line where some breaks in the rain are expected during the afternoon. This is where we will see the warmest high temperatures, with temperatures in the middle 50s to potentially the lower 60s by the mid afternoon. However, if rain ends up moving farther east than expected this afternoon, it could end up a couple of degrees cooler than this. For the rest of the area, it is highly certain with the rain that highs will be cooler than average, ranging from around 40 west to lower 50s east. Some destabilization may occur parts of northwest Iowa and adjacent areas of southeastern South Dakota and southern Minnesota, leading to a couple hundred J/kg of MUCAPE to develop by the evening. This could result in a few thunderstorms as the surface low lifts northeast nearby to this area during the evening; however, severe weather is not expected. This surface low will lift northeast of the area by daybreak Tuesday, drying the area out entirely.

As the rain exits, can't entirely rule out a few snowflakes mixing in with the rain late Monday evening/early overnight in our far western areas (<15% chance), but impacts are not expected as temperatures will be safely above freezing if and when this were to occur. Clouds will linger though the night even as the rain ends, and this combined with no real big push of cold air advection behind this system will mean the NBM may be a bit too cold for the morning lows for Tuesday. In collaboration with neighbors, did raise the lows a couple of degrees. With that, look for lows to range from the middle 30s west to upper 40s southeast. A few pockets of lower 30s will be possible in south- central South Dakota by sunrise Tuesday, but precipitation will be long gone by then.

DISCUSSION

Issued at 155 PM CDT Sun Oct 25 2026

CURRENTS-MONDAY: Another dreary and wet day continues! Taking a look across the area, we're continuing to enjoy a brief break this afternoon as the rain shield lifts into northeastern SD and central SD. While these conditions will likely persist through late afternoon, should see a shift eastwards during the evening hours locking us into intermittent showers for most of the night. From here, should see rain coverage continue to expand into Monday morning as a developing mid-level low lifts out of the Nebraska panhandle into central and eastern SoDAK. Given the better lift and strengthening warm air advection (WAA) with the wave, pockets of moderate (and at times heavy) rain likely develop throughout the day mainly west of I-29. Otherwise, this will be a longer duration rainfall event (24-30 hours) so flooding concerns are not expecting. However, localized ponding in urban and low-lying areas will be possible at times especially where the heaviest accumulations develops.

Looking at overall amounts, most deterministic and ensemble guidance continues to show high agreement in areas along west of a Yankton to Sioux Falls to Windom, MN line being the focus for 1+ inches amounts during the period with some low to moderate potential (30%-50%) for locally higher (up to 2 inches) west of the James River Valley. As this activity continues to gradually lift northeastwards, could also see some convectively enhanced showers develop by Monday evening mainly along and east of I-29 as the dry slot lifts through portions of the area and some weak instability develops. Conditions should gradually clear from southwest to northeast starting as early as Monday evening. Lastly, a large temperature gradient will set up across the region on Monday due to the increased precipitation chances. As a result, daily highs will vary between the mid 40s to mid 50s in the wettest areas (west of the line) and mid 50s to low 60s in the driest areas (lower Missouri River Valley and northwestern IA).

TUESDAY & WEDNESDAY: Looking into Tuesday, any lingering showers should continue to taper off northeastwards during the morning hours bringing the return of quieter conditions. Cloud cover should gradually decrease west of I-29 as southerly surface winds return. This combined with a bit of lingering WAA will help temperatures slightly recover with highs expected to be in the low 60s to low 70s. A tightening SPG could also lead to some marginal breeziness in the afternoon with gusts between 20-30 mph expected. By Wednesday, could see the return of some scattered showers during the afternoon hours as a quick shortwave drags a cold front through the Northern Plains. However, any resulting accumulations would be light with most ensemble guidance showing low to moderate confidence (30%-50%) in measurable precipitation mainly east of I-29. Lastly, we'll see similar temperatures to Tuesday with highs peaking in the low 60s to low 70s.

THURSDAY ONWARDS: Heading into the extended period, quasi-zonal flow will return through about Friday before Upper-level ridging returns to the plains. Some medium to long-range deterministic guidance continues to latch on to some additional precipitation chances between Friday and Saturday. However, there are some timing discrepancies among guidance. We'll just continue to watch this period for now especially since its a big holiday for the kiddos. Otherwise, we'll continue to lean slightly above normal temperature- wise through Sunday with highs mainly in the 60s with some low 70s across northwestern IA at times.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1257 PM CDT Mon Oct 26 2026

A mix of VFR to IFR conditions will continue to degrade as clouds thicken and lower. IFR ceilings and visibility are expected to prevail through the late afternoon and overnight hours, with brief periods of LIFR possible. Along with the low, thick clouds periodic rain showers will continue into the early hours of Tuesday. As the system responsible moves to the northeast showers will gradually become lighter with periods of drizzle possible before moving east of the CWA altogether, around sunrise. Though precipitation will end, ceilings remain in the IFR category for much of the remaining period.

Winds are out of the northeast and slightly breezy with gusts of 15- 20 kts expected. Winds will decrease after sunset as the surface low pushes through the region, becoming light and variable through Tuesday morning. Breezy southwest winds gusting to 25 kts will push into central South Dakota near the end of the period.

FSD WATCHES/WARNINGS/ADVISORIES

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