textproduct: Sioux Falls

KEY MESSAGES

- Areas of frost or near-freezing temperatures will again be possible early Thursday morning

- Near to above normal temperatures return Thursday into the weekend with highs mainly in the 60s to 70s. Rain chances will be sparse, with a low chance south of I-90 later Saturday.

UPDATE

Issued at 417 AM CDT Wed May 6 2026

Early morning temperatures are a bit tricky as we've had an area of mid-level clouds sag southward into areas near to north of I-90. Clouds have limited the temperature drop in these areas, while some favored drainage locations south of the advancing clouds have dipped into the mid-upper 20s. Given the limited potential for additional protective action at this late night hour, did not chase the temperatures with adjustments to the ongoing frost and freeze headlines.

No significant changes to the forecast in the upcoming days. Temperatures tonight may again be somewhat dependent on cloud cover, but lower-mid 30s on a broad scale seem reasonable.

Given the persistent dry air mass, did blend in some HRRR/RAP and other short-term models to lower afternoon dew points today and tomorrow. This will produce critical relative humidity levels Thursday afternoon, as low as 15 to 20 percent. However, Thursday also looks to be the lightest wind day of the next several, and with decent green-up in most locations, do not anticipate significant fire weather concerns.

DISCUSSION

Issued at 120 PM CDT Tue May 5 2026

CURRENTS & TONIGHT: Another mild and breezy day continues! Taking a look across the area this afternoon, cloud cover continues to filter in as breezy northwesterly winds persists with gusts between 20-30 mph. While drier conditions this afternoon could promote some locally elevated fire concerns, greener fuels and milder temperatures will likely keep any fire danger risk in the low to moderate categories. Otherwise, the main concern tonight continues to be the potential for frost/freeze conditions. With the return of near to sub-freezing temperatures (26-32 degrees) and lighter surface winds tonight, areas of frost are expected to develop across most areas especially along and north of I-90. While there is still some uncertainty with coverage mainly due to 5-10 degree dew point depression, still thinking the conditions will do just enough for sensitive plants to be affected. As a result, have collaborated with neighboring offices to issue both a Freeze Warning and Frost advisory from 1 am to 7 am CDT. My thoughts are the warning is in place where confidence is highest on sub- freezing temperatures and widespread development with small dew point depressions. The advisory is in place for areas where patchy to scattered areas of frost are possible. With all this in mind, make sure to cover/bring in any sensitive vegetation!

WEDNESDAY-THURSDAY: Looking into the midweek, lingering cold air advection (CAA) and northwesterly surface winds will keep the milder stretch going through at least Wednesday night with highs in the low to upper 50s and overnight lows in the low to mid 30s. Similar to tonight, we could see additional chances for frost by Thursday morning. However, border-line temperatures and a higher dew point depression (8-12 degrees) will likely make coverage more patchy than scattered with the main focus being along our River Valleys. By Thursday, we'll start to trend warmer as a weakening ridge and a return to southwesterly to westerly flow brings an influx of warmer air to the area. This will lead to beautiful conditions as highs peak in the 60s to low 70s for the day with lighter winds.

THE WEEKEND ONWARDS: Heading into the extended period, an active pattern will once again return as continuous northwesterly flow aloft 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 (20%-30%) for areas along and south of I-90 to see rain. This is further agreed upon within ensemble guidance with most members showing a 30%-60% chance for at least measurable precipitation. Lastly, we'll continue our warming trend through Monday with highs mainly in the 60s to low 70s.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1233 AM CDT Wed May 6 2026

VFR conditions are expected to prevail for this period. Mid to high level clouds will also prevail with a period of lower ceilings mid morning to early afternoon around 5000 ft AGL. Ceilings improve as clouds clear out in the late afternoon.

Overnight winds will be light and variable. After sunrise winds become northwesterly and gradually increase. Afternoon gusts of 17- 22 kts will be widespread across the region. Winds decrease after sunset becoming light and variable near the end of the period.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Frost Advisory until 7 AM CDT this morning for SDZ050-063>071. Freeze Warning until 7 AM CDT this morning for SDZ038>040- 052>062. MN...Frost Advisory until 7 AM CDT this morning for MNZ090. Freeze Warning until 7 AM CDT this morning for MNZ071-072-080- 081-089-097-098. IA...Frost Advisory until 7 AM CDT this morning for IAZ001>003- 012>014-020>022. NE...None.