textproduct: Sioux Falls

KEY MESSAGES

- We're on track for our first widespread freeze of the season mainly due to light winds and sub-freezing temperatures tonight. As a result, a Freeze Warning will be in effect from 1am-8am CDT.

- A few sprinkles to very light showers will be possible on both Saturday and Sunday. However, any accumulations would be limited.

- After above normal temperatures over the weekend, more seasonable conditions return by midweek as mostly dry conditions persist.

UPDATE

Issued at 819 PM CDT Fri May 1 2026

The forecast for tonight remains on track. Clouds continue to diminish across the area, with the last of the cumulus fading away over northwest Iowa within the next hour or so. With high pressure overhead leading to light to calm winds through the overnight hours, we are still looking to see a widespread freeze by daybreak Saturday. Temperatures have been falling thus far as expected and so the current Freeze Warning looks to be in good shape. Remember to take the steps to protect sensitive vegetation before you head to bed for the night!

After the chilly start to our Saturday, should warm up nicely as southwesterly flow returns and warm air advection increases. Look for highs on Saturday to be in the 60s to low 70s, warmest near and west of the James River.

DISCUSSION

Issued at 1258 PM CDT Fri May 1 2026

CURRENTS & TONIGHT: Another mild day continues! Taking a look across the area, a beautiful day continues with temperatures mainly in the upper 40s to low 50s across the area with breezy northerly winds. Expect winds to gradually decrease into the evening as a surface high moves overhead which will us to our main concerns. Similar to yesterday, the combination of lighter surface winds and near to below freezing temperatures (28-32 degrees) will likely lead to widespread frost develop overnight. However, the main difference comes with the mostly clear conditions unlike yesterday. After collaboration with neighboring offices, a Freeze Warning will be in effect from 1am-8am CDT for most areas. With this in mind, make sure to bring in/cover any sensitive outdoor vegetation and to turn off your sprinklers for the night.

SATURDAY & SUNDAY: Looking into the rest of the weekend, northwesterly flow will continue aloft as the ridging continues to flatten across the western CONUS. Temperatures will trend warmer by Saturday as southwesterly surface winds and increasing mid-level warm air advection (WAA) help highs return to the 60s and low 70s. While a mostly dry cold front will swing through by late evening, can't completely rule out a few spits to very light showers overnight especially across southwestern MN. Nonetheless, accumulations will be limited (if any) given the lack of saturation depicted in soundings. A similar set up will occur on Sunday as another push of warmer air aloft will help highs once again reach the 60s to low 70s. However, a slightly strong cold front will swing through starting as early as Sunday night potentially leading to a few additional showers by Monday morning. Lastly, the influx of colder air could affect temperatures into early next keeping highs closer to seasonable thresholds (low to upper 50s) through the midweek.

NEXT WEEKEND: Heading into the extended period, an active pattern will persist aloft for most of the week as the Hudson Bay Trough strengthens and upper-level ridging builds over the western CONUS. This will likely keep us locked into predominantly northwesterly flow aloft with multiple system rotating through the northern plains. However, with medium to long-range guidance continuing to suggest limited moisture with each wave; not expected much past a few diurnally driven chances (<30%) on Monday and potentially Thursday. Lastly, after a brief cool down to start the week; we'll continue to trend warmer from Thursday onwards with highs in the 60s to low 70s into the weekend.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 620 PM CDT Fri May 1 2026

VFR conditions expected through the period. Afternoon CU will fade through the early evening, and winds will turn light and variable into tonight. Winds will pick up out of the southwest through the day on Saturday, gusting to around 20 kts at times especially north of I-90 during the afternoon. Clouds will begin to increase near the Highway 14 corridor towards the end of the period as a cold front approaches the area, but remain VFR.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Freeze Warning from 1 AM to 8 AM CDT Saturday for SDZ038>040- 050-052>071. MN...Freeze Warning from 1 AM to 8 AM CDT Saturday for MNZ071-072- 080-081-089-090-097-098. IA...Freeze Warning from 1 AM to 8 AM CDT Saturday for IAZ001>003- 012>014-020>022-031-032. NE...Freeze Warning from 1 AM to 8 AM CDT Saturday for NEZ013-014.