textproduct: Sioux Falls

KEY MESSAGES

- Isolated severe storms will be possible this afternoon over parts of southwest MN and northwest IA. The main threat should come to an end by 4-5 pm.

- Near critical to critical fire weather concerns are expected this afternoon and evening especially across most southeastern SD and parts of southwestern MN. Avoid any outdoor burning!

- A return to more seasonable temperatures with highs in the mid 50s to lower 60s is expected Friday through the middle of next week.

- A very good chance (60%-90%) for showers and thunderstorms returns Sunday into Monday. Some locally heavier rain will be possible.

DISCUSSION

Issued at 1256 PM CDT Thu Apr 23 2026

The severe weather threat for mainly northwest IA will gradually come to an end late this afternoon as the dry line/cold front race southeast. So far the front is a bit ahead of schedule so some potential for most of the activity to be out of our area by 4-5pm. The storms that do develop this afternoon will have about 1500-1750 J/kg CAPE and moderate shear so hail to the size of half dollars and wind gusts to 60 mph seem like the main threats. With the potential for some surface connection with the updrafts a very isolated tornado cannot be ruled out.

The fire weather threat will diminish this evening as temperatures fall and dew points increase behind the cold front. This will lead in to a quiet and cooler Friday with highs mainly in the upper 50s to mid 60s.

Rainfall probabilities for the weekend into Monday continue to indicate good chances for a meaningful rain. Not completely ready to jump on board just yet, but the data is starting to make it look difficult to miss out. Both the Canadian and EC Ensemble indicate a widespread 1" plus for pretty much the entire area while the GEFS suggests there will be a sharper cutoff from northwest to southeast with the higher amounts from northwest IA southward. Although the latest GEFS has increased rainfall amounts compared to yesterday across the entire area, just not as much as the Canadian and EC. Even a quick look at the 10th percentile suggests pretty much a quarter to a half an inch everywhere except closer to highway 14.

Right now the severe weather threat looks pretty low during this time. Will keep an eye on Sunday night into Monday as low pressure deepens and moves into the area. Maybe enough forcing to generate a few stronger updrafts. But all in all the instability tends to stay locked up from roughly I-80 southward.

The low pressure that brings the area the potentially meaningful rainfall will drift east towards the Great Lakes Tuesday into Thursday, leaving the area in drier northwest flow. This will continue the trend of near to a bit below normal temperatures. Precipitation chances will remain spotty through this time with a few weak waves expected to rotate southeast through the strong northwest flow.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1226 PM CDT Thu Apr 23 2026

Scattered showers and thunderstorms can be expected over parts of northwest IA and southwest MN through about 22-23z, then most of the activity will shift southeast of the area. Along and ahead of this convection MVFR ceilings will be likely. Otherwise strong westerly winds are expected behind this convection with gusts of 30 to 40 mph likely through sunset across the entire area. After sunset gusty winds to 25-30 mph will still be possible but diminish further late tonight with VFR conditions expected.

FSD WATCHES/WARNINGS/ADVISORIES

SD...Red Flag Warning until 8 PM CDT this evening for SDZ039-040- 054>056-060>062-065>069. Red Flag Warning until 5 PM CDT this afternoon for SDZ038-050- 052-053-057>059-063-064. MN...Red Flag Warning until 8 PM CDT this evening for MNZ071-072- 097. IA...None. NE...None.