textproduct: Sioux Falls

KEY MESSAGES

- The remainder of the work week features cooler than normal temperatures and occasional risks of very light rain.

- Warmer temperatures return by next weekend with high temperatures around 10 degrees above normal in the upper 60s to 70s.

UPDATE

Issued at 329 AM CDT Tue Apr 28 2026

No significant changes to the forecast this morning. Stratus continues to move off to the east, with a few high clouds moving in across south central SD and southern MO River Valley, leading to mostly clear skies. Still can't entirely rule out some patchy fog with temperatures falling into the 30s; however, winds should remain just strong enough to preclude fog development. If fog develops, expect it to be through the MO and James River Valleys, east toward I-29.

Minor changes early this morning to pops for today into early this evening, as a mid level wave moves across the southern part of the area and across northern NE/IA earlier in the day, with a second wave tonight. Soundings show some weak instability (less than 100 J/kg) which may be enough with weak WAA to get some isolated to scattered sprinkles/showers to develop. Some question on how quickly the unstable layer can saturate, so not confident in going any higher with pops at this time. No impacts expected. Cooler again today with lower level clouds increasing. Highs in the upper 40s to upper 50s.

May have to watch for potential patchy fog and/or frost development tonight if we can see skies clear a bit more than forecast with temperatures. Winds may also remain just stronger enough again tonight to prevent any development. For now, will keep mention out of the forecast given low confidence in occurrence. Temperatures fall into 30s again.

DISCUSSION

Issued at 1215 PM CDT Mon Apr 27 2026

THIS AFTERNOON: Upper level troughing and associated surface low pressure continues to move east and away from the Tri-State area this afternoon. At mid-day we're beginning to see 30+ knot wind develop in central SD, which will begin to extend eastward through the evening hours. Some gusts over 40 knots could be possible through the higher elevation of the Ridge. Temperature will continue to slowly fall as stratus remains in place.

TONIGHT: Subsidence will begin to chew away on lower stratus early this evening, eventually leading to clear skies throughout the CWA near or after midnight. Temperatures may fall below freezing in areas north of I-90. With the recent rainfall and clear skies, should winds fall off adequately, then areas of fog may develop.

TUESDAY-FRIDAY: A broad upper trough centered across the eastern half of the CONUS will keep the region cooler than normal through the rest of the week. A few weak perturbations passing through the southern side of this trough will lead to very light rain chances. These rain chances are focused along the MO river valley Tuesday afternoon and evening, most of the Tri-State area Wednesday afternoon and night with these chances continuing into Thursday. Overall QPF amounts will be light with the 24 hour probability of QPF over 0.10" no more than 15% ATTM.

SATURDAY-MONDAY: Confidence in the temperature forecast for the upcoming weekend remains medium at best. Guidance remains split on the potential for the expansion of western CONUS ridging to the east, increasing overall spread in ensemble guidance. That said, as compared to 24 hours ago, the spread has narrowed slightly, with an overall cooling in temperatures in the 25/75th percentile ranges of the NBM. While PoPs remain below mentionable levels, the passages of 1-2 cool fronts Saturday and Monday could lead to future low end mentions in future forecasts.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 616 AM CDT Tue Apr 28 2026

Largely VFR conditions through the period with increasing mid/high clouds this morning. MVFR conditions are expected by early this afternoon in south central SD, expanding with showers through the MO River Valley. Maintained the PROB30 groups for KFSD and KSUX for -SHRA this evening, although recent model trends are keeping most activity away from KFSD. Otherwise, most of the area will see some lower end VFR stratus for the latter half of the period.

Winds remain light and generally northwesterly, becoming variable overnight.

FSD WATCHES/WARNINGS/ADVISORIES

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