textproduct: Sioux Falls

KEY MESSAGES

- A few lingering sprinkles, mostly along and south of Highway 20, should be southeast of the region after midnight.

- Patchy areas of frost will be possible tonight mainly across the Highway-14 corridor. Additional chances for scattered areas of frost/freeze conditions are expected by midweek. However, some uncertainty remains. Make sure to cover/bring in any sensitive vegetation!

- After below normal temperatures through midweek, near to above normal temperatures will continue into the weekend with highs mainly in the 60s to 70s.

UPDATE

Issued at 844 PM CDT Mon May 4 2026

Very few changes have been made to the forecast this period. Low temperatures for tonight have increased slightly, limiting the areas at risk for possible frost to along and north of Highway 14. Here temperatures may dip to freezing and just below for a couple of hours just before sunrise. The catch is dew point depression remains high at 8-10 degrees F. Making it unlikely actual frost will develop. Considering the brief and spotty nature of the coldest temperatures have foregone a frost advisory. However, the brief window of freezing temperatures could still nip tender plants. If you are able cover or bring in your plants tonight.

DISCUSSION

Issued at 126 PM CDT Mon May 4 2026

CURRENTS & TONIGHT: Another mild and breezy day persists! Taking a look across the area, the breeziness continues behind this morning's cold front with most observations showing northerly wind with gusts between 25-35 mph along with temperatures mainly in the 50s to 60s. With deeper mixing and lower dew points, near-critical RH values continue with values in the 25-30 percent range. While the combination of the ingredients above have led to locally elevated fire concerns; decided to hold off on any fire-related headlines mainly due to greening fuels. Otherwise, can't completely rule out a few scattered sprinkles along and south of the Highway-20 corridor this evening. Nonetheless, with limited saturation according to sounding; expect any accumulations to very light at best. Lastly, as cloud cover thins and surface winds lighten overnight; an influx of cooler air will lead to temperatures mainly in the low to upper 30s for the night. With this in mind, could see some patchy frost develop mainly along the Highway-14 corridor overnight. While the extent is still in question mainly due to a higher dew point depression, decided to also hold off on an frost/freeze headlines at this time.

TUESDAY-THURSDAY: Looking into the midweek, we'll continue to sit in northerly flow aloft as a predominantly troughy pattern continues aloft. With lingering mid-level cold air advection (CAA) and predominantly northwesterly flow in place at the surface, expect temperatures to temporarily decrease through at least Wednesday with highs mainly in the low to upper 50s. With lows expected to be near to below freezing (26-32 degrees) each night, additional chances for more widespread frost/freeze development are expected especially by Wednesday. However, with an 8-10 degree dew point depression and variable cloud cover at times; there are still some questions as to extent of the frost/freeze. Nonetheless, we should be about to hit a turning point by Thursday as increasing mid-level warm air advection (WAA) and the return of southwesterly to westerly winds help highs climb back into the 60s. Lastly, any precipitation chances continue to look rather limited for the period.

THE WEEKEND: Heading into the extended period, an active pattern will once again return as northwesterly flow helps usher in multiple waves through our area. The strongest of which looks to arrive between Saturday to Sunday. While there is still some variability among long-range guidance, this still looks like our best chances (30%-40%) for areas along and south of I-90 to see rain. This is further agreed upon within ensemble guidance with most members showing a 20%-40% chance of 0.10" of an inch or greater of QPF. While not a drought buster by any means, any potential rain chances are encouraged at this point. Lastly, we'll continue our warming trend into the weekend with highs mainly in the 60s to low 70s.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 623 PM CDT Mon May 4 2026

VFR conditions are expected to prevail for the period. Scattered light rain showers are ongoing, mostly over northwest Iowa. These showers will continue to move southeast over the next few hours. Dry conditions are expected to then prevail for the remainder of the period.

Winds are currently out of the northwest gusting between 25-35 kts. These will drop off quickly after sunset, becoming light to light and variable overnight. Afternoon gusts will increase again to between 15-20 kts and will continue through the end of the period.

FSD WATCHES/WARNINGS/ADVISORIES

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