South Sioux City, NE Weather

Key Messages

- Scattered showers continue to spread eastwards this evening. Widespread accumulations are expected through Monday night with areas along west of a Yankton, South Dakota to Sioux Falls, South Dakota to Windom, Minnesota line being the focus for 1+ inches. Locally higher amounts remain possible near and west of the James River Valley.

- 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 920 PM CDT Sun Oct 25 2026

Light rain continues to fall west of I-29 this evening. These light rain showers continue to push eastwards. As of now, only light rainfall amounts up to a few hundredths to about a tenth of an inch has fallen. Expect this area of light rain to continue to push eastwards and expand in coverage through the rest of the night. The only small change in the forecast looks to occur during the overnight hours. Weak to little dendritic forcing will be in place along and north of a Marshall, Minnesota, to Madison, South Dakota to Chamberlain, South Dakota line. Thus, rainfall amounts will be a tad bit lower, though nothing more than about a tenth of an inch lower. The main upper level wave remains on track and will eject into the Plains tonight. Low level warm air advection (WAA) will strengthen, especially for tomorrow morning, tightening the 850 mb temperature gradient, and strengthening the 850 mb front. Dendritic forcing will also increase along with this low level forcing as well, allowing for widespread rain to develop.

This rain will persist for the entirety of Monday before rain begins to exit the forecast area to the northeast late Monday evening and night. Rainfall amounts remain on track with locations along and west of a Yankton to Sioux Falls to Windom, MN line remaining the focus for 1+ inches amounts. Still seeing the potential in the latest guidance for isolated rainfall amounts up to about 2 inches near and west of the James River. Lower rainfall amounts down to about a half an inch or less is expected east of the previously mentioned line, where the forcing will be weaker. With abundant cloud cover in place, high temperatures remain on track to only warm to the 40s and 50s across the majority of the area. Parts of northwest Iowa may be the exception as highs could once again warm to the 60s if cloud cover can decrease enough. Low temperatures will again fall to the 30s and 40s Monday night.

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

Issued at 1052 PM CDT Sun Oct 25 2026

Light showers continue to push eastwards late this evening. Conditions remain a mix of mostly VFR and some MVFR ceilings and visibilities currently. Expect these showers to push eastwards and expand in coverage through the rest of the evening hours. Rain will persist through the night and the entirety of the daylight hours on Monday. Ceilings will lower to MVFR/IFR/LIFR levels through the night in the rain. Visibilities look to lower to MVFR thresholds in the rain as well. Could see further reductions in visibility down to IFR levels in the heaviest rain. Winds will pick up out of the east tomorrow morning with gusts strengthening to 15-25 knots.

Rain will begin to push northeast of the area Monday evening. While chances for rain may be ending, ceilings will remain reduced through the end of the TAF period.