textproduct: Sioux Falls

KEY MESSAGES

- One more night of near freezing to frosty conditions in the region, though cloud cover may have an impact on potential. Continue to protect sensitive vegetation.

- A gradual warming trend begins Thursday and continues through next week. Eventually we'll end up with temperatures 5-10 degrees above normal.

- Rain chances continue to look minimal through the 7 day forecast despite the passage of several weak waves. Severe weather risks also remain minimal well into next week.

UPDATE

Issued at 855 PM CDT Wed May 6 2026

Very few changes to the forecast this period. Some high resolution guidance has begun to speed up the timing of the mid-level WAA to a couple hours before midnight. However, with calm winds and little to no mixing it is unlikely to impact our chances for frost tonight. Modest moisture advection in the 650-550 mb layer coupled with weak convergence along a boundary and upward directed omega will result in mid-level clouds developing a few hours before sunrise. These will work to slow our temperature falls, limiting chances of frost to patchy areas. The area most likely to see frost remains along and north of I-90 with chances increasing as you move north. The current Frost Advisory from 3 am until 8 am looks to be in good shape. Highs for Thursday remain on track to climb into the 60s for most of the region.

DISCUSSION

Issued at 115 PM CDT Wed May 6 2026

THIS AFTERNOON: Considerable diurnal based CU in the region as cold air aloft sweeps through the region. While moisture depth remain shallow, not out of the question to see a sprinkle or two.

TONIGHT: Clouds clear this evening with a gradual tapering of winds at the surface. Temperatures will begin to drop fairly quickly after 10pm. However, a corridor of mid-lvl warm advection develops after 06z and combined with positioning of upper jet should lead to mid- upr cloud development into daybreak. This cloud cover will then slow the diurnal trend of temperatures through the 30s. Frost may still be possible, but large dew point depressions may limit overall potential. Some areas could still see a brief time near or just below freezing, mostly north of I-90, so will issue a frost advisory to at least raise awareness of danger to sensitive vegetation.

THURSDAY-FRIDAY: We'll begin to see a gradual warm up on Thursday and Friday, though the presence of a northwesterly surface and low-lvl wind makes me question just how far we'll rise. Recent NBM runs have been a bit too warm each day, which makes me trend towards more CONSshort/CAM guidance. Temperatures rise into the 60s in most areas. A weak wave passing through western South Dakota and Nebraska into Friday may bring a bit more cloud cover and a few sprinkles to the MO River valley, but most stay dry. 925:850 temperatures rise a few more degrees Friday, with more of a westerly wind supporting a bump in temperatures towards the lower 70s.

SATURDAY-SUNDAY: We remain stuck in a quasi-northwesterly flow pattern through the upcoming weekend. A warm start to Saturday may be tempered by the passage of a frontal boundary in the afternoon bringing slightly cooler temperatures and shifting winds to the north into the evening. A passing sprinkle/shower/virga may be possible into the overnight hours. The northerly winds continue on Sunday dropping temperatures back towards seasonal normals in the middle to upper 60s.

MONDAY-WEDNESDAY: It looks like we'll begin to break free of the northwesterly mid-lvl flow next week with the expansion of a mid-lvl ridge eastward. Rising heights will allow much warmer low-lvl temperature to spread across the Plains, suggesting that we'll have an extended period of next week with highs above normal. In fact, we do begin to see some 30-40% probabilities of 80+ degree temperatures into the MO river valley by Wednesday. Rainfall risks into next week with the expanding ridge will remain low. Partly due to a lack of strong forcing, but also due to the lack of meaningful moisture streaming northward. The probability of more than 0.50" of QPF in both the GFS/EC/CMC ensembles through the upcoming 7 day time period are all less than 20%.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 625 PM CDT Wed May 6 2026

VFR conditions are expected for the period. Mid-level clouds will thin but hang around through the first half or so of the period before becoming clear. Winds will become light and variable after sunset, then turn northwesterly Thursday afternoon at 5-10 kts.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Frost Advisory from 3 AM to 8 AM CDT Thursday for SDZ038>040- 052>060. MN...Frost Advisory from 3 AM to 8 AM CDT Thursday for MNZ071-097. IA...None. NE...None.