textproduct: Sioux Falls

KEY MESSAGES

- Isolated showers continue through 7 AM, mainly west of US Highway 81. Light rainfall amounts expected (less than a tenth of an inch).

- Patchy fog is expected through mid morning, mainly east of the James River. Probability of visibility below one mile is as high as 75% east of I-29.

- Periods of rain return tonight into mid week, heaviest tonight into Monday. Through Wednesday night, high probability (over 60%) of totals over an inch and low to moderate (15-55%) chances of two inches or more, greatest north and west of Sioux Falls. Locally heavy rain may lead to ponding of water.

- Isolated storms are possible tonight into Monday night. Although risk remains low, a stronger storm or two are possible near and south of US Highway 20 Monday afternoon.

- Breezy to gusty winds expected Monday and Tuesday. Wind gusts of 30 to 40 mph, with gusts around 45 mph across south central South Dakota.

UPDATE

Issued at 229 AM CST Sun Nov 1 2026

No significant changes to the forecast to kick off the month of November. Isolated showers are lifting north of US Hwy 14, although watching the next area lift north across NE. Any rainfall amounts will be light. Beginning to see some lower stratus and fog expand over the eastern portions of the area, with probability of visibility below a mile this morning as high as 75%. Winds are remaining a touch stronger than expected which may limit the coverage of fog. Fog should lift by mid to late morning, with stratus lingering through the day. Breezy winds prevail west of the James River.

Rain expands from southwest to northeast late this evening and tonight with the first push of WAA. Rain continues into mid week as the mid and upper level lows remain over the Plains. Main changes with the guidance is the continued downward trend/northwest shift of the potential of heavier rain (totals through Wednesday night of 2 inches or more). Localized ponding of water due to locally heavy rain may occur, but not expecting widespread issues or flash flooding. Heaviest rainfall expected tonight into Monday evening.

Still watching the potential for a stronger storm or two Monday afternoon as the surface warm front lifts north and the low moves into SD. Low confidence remains in the severe weather threat Monday afternoon near/south of US Hwy 20, which is discussed more below.

DISCUSSION

Issued at 215 PM CDT Sat Oct 31 2026

CURRENTS & TONIGHT: Taking a look across the area, the dreary and wet conditions persists as lingering showers gradually lifting through the Highway-14 corridor this afternoon and areas of fog continue to erode. While a brief lull in activity could develop through the late afternoon hours, short-range guidance continues to show a few additional showers developing by early evening mainly west of highway-81 as another wave swings through. Any resulting accumulations would be light at best. Lastly, with overcast skies likely continuing through the evening hours; decided to slightly increased overnight lows by blending in some of the CONSshort resulting in temperatures in the low to mid 50s with the warmest conditions along our River Valleys.

SUNDAY-TUESDAY: Not many forecast changes expected into Sunday as increasing warm air advection (WAA) aloft keeps us locked into the overcast and dreary conditions for most of the day. While most areas should remain dry during the day, a few durnally-driven sprinkles to light showers could develop in the lower cloud bases during the afternoon with limited accumulations. From here, the focus continues to be on the increased rain chances from Sunday night into Monday. Looking aloft, most of our rain chances (70%-100%) will be in response to a developing Colorado Low lifting from the Nebraska Panhandle into central and eastern SoDak throughout the day. Widespread rain is expected as increase lift in the warm air advective wing leads to pockets of light to moderate rain for the first half of the day. From here, we'll likely lose mid-level saturation during the afternoon hours as the dry slot progresses through the area. With this in mind, any lingering activity will begin to dissipate as it lifts northeastwards.

A few isolated thunderstorms can't be completely rule out across northwestern IA giving the low CAPE/high shear environment and increased lift ahead of the triple point. However, confidence continues to decrease in any stronger activity mainly due to afternoon development across eastern Nebraska and northwestern Missouri effectively cutting off our moisture pool. Otherwise, additional precipitation chances will return from Monday night into Tuesday morning as the cold front swings through. Shifting gears to amounts, ensemble guidance continues to show moderate to high confidence (60%-80%) in at least 1 inch of QPF mainly along and west of I-29 with lesser amounts (0.50" of an inch or less) elsewhere. With trends continue to pull the highest amounts towards central SD with the deformation zone/warm-front, wouldn't be surprised if QPF amounts continue to trend downwards and northwestwards moving forward especially as more short-range guidance gets ingested into the NBM QPF. Nonetheless, our flash flood risk continues to look low with mainly concern being localized ponding in low-lying areas. Lastly, with a tightening SPG on both Monday and Tuesday; expect surface winds to strengthen with gust between 30-40 mph expected on both day.

WEDNESDAY ONWARDS: Heading into the extended period, an active pattern continues aloft with medium-range guidance struggling to resolve the location of the upper-level low. While confidence is low, can't rule out some wrap around showers throughout the day on Wednesday especially east of I-29. Quieter conditions will return by Thursday as mid-level ridging progresses through the area. This along with the return mid-level warm air advection (WAA) should lead to slightly warmer temperatures heading into the weekend with highs increase from the low to mid 50s by Wednesday into the low to mid 60s by Thursday.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1038 PM CDT Sat Oct 31 2026

Stratus will continue to thicken and lower through the overnight. Mostly VFR ceilings will degrade down to widespread MVFR as a result. In addition, ensemble guidance continues to indicate a 60- 70% probability of patchy fog development east of Highway 81. The combination of low stratus and fog could result in visibility dropping to 2 miles or less at times. Stratus and fog will be slow to lift Sunday morning and may hang around into the late morning. Ceilings will improve as fog lifts but will likely remain mostly MVFR. Another round of showers and thunderstorms push in from the southwest near the end of the period.

Current radar shows light echos along and east of the James River Valley. These will move north through the overnight, dissipating from south to north a few hours before daybreak. Accumulation will be very light, a trace to a couple hundredths. Southerly winds will remain on the breezy side now through the overnight. Gusts of 15-20 kts are expected for areas west of I-29, with gusts of 15 kts or less to the east. Winds will increase with daytime heating with widespread afternoon gusts of 15-25 kts. Strongest winds expected over central South Dakota. Winds will remain breezy through the end of the period.

FSD WATCHES/WARNINGS/ADVISORIES

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