textproduct: Sioux Falls

KEY MESSAGES

- Multiple chances for showers and thunderstorms are in the forecast from Thursday onward. A few stronger storms may be possible Saturday afternoon into early Sunday morning.

- A gradual warmup is expected Thursday through the weekend. Above average temperatures are expected Friday through Monday.

- A sharp drop in temperatures likely Monday into Tuesday.

UPDATE

Issued at 900 PM CDT Wed Apr 8 2026

Elevated fire danger has come to an end this evening as winds continue to decrease and humidity increases. Still looking at some showers developing during the afternoon timeframe tomorrow as a weak shortwave pushes into the forecast area. Rainfall amounts look to remain light at a tenth of an inch or less. With minor instability values (up to 300 J/kg at the most) a few weak thundershowers are possible which could deliver the first rumbles of thunder of the season.

Friday remains on track to be a quiet day as upper level ridging builds aloft. High temperatures look to warm back to the 50s to perhaps touching 60F in a few spots. While some lower humidity values down to about 30% are possible, winds will be light as surface high pressure will be passing through the area during the daylight hours. Thus, fire danger is not expected.

DISCUSSION

Issued at 118 PM CDT Wed Apr 8 2026

Breezy northwest winds gusting 25-35 mph will usher in a much drier air mass this afternoon. Relative humidity levels will fall to near critical to critical for a brief period this afternoon. While no fire headlines are planned at this time, caution is still needed to prevent the spread of wildfire. This afternoon a low chance (<25%) of isolated to scattered light rain is possible over northwest Iowa. If showers can overcome the dry boundary layer, very little if any accumulation is expected. Highs this afternoon will climb into the 50s to 60s, with the highest temperatures over northwest Iowa. Winds become light and variable overnight with clear skies. This will help lows cool down to the 20s.

An active pattern looks to be the story for the rest of the week and into next week. Thursday a shortwave passes through the region bringing weak elevated instability and moderate WAA in the mid- levels. This may be enough to trigger showers and possibly thunderstorms. While isolated to scattered storms are possible across the region, any thunderstorms will most likely remain along and south of Highway 20. Severe weather is not expected, however a few stronger storms may produce wind gusts of 40-50 mph and small hail to the size of dimes.

Friday an upper ridge and surface high pressure build into the region. As it does so winds will become easterly to southeasterly. Subsiding air will warm and dry out conditions at the surface. Minimum relative humidity values are expected to fall to around 30% Friday afternoon. Highs will be in the 50s with light winds. Thanks to the milder temps and light winds fire danger will remain low to moderate for most of the forecast area. The exception will be south central South Dakota, where the high category may be reached. Though fire risks are lower, please continue to use caution.

Zooming out and looking at the overall pattern we see a large trough digging south over the Pacific Northwest. As it does so, vorticity waves propagate off the parent wave, compressing the pressure gradients from the surface through the mid-levels. The LLJ and surface winds will increase in response. Afternoon wind gusts of 25- 35 mph are expected with locally higher gusts possible. Good mixing and WAA will help afternoon highs climb into the 60s and 70s. Dewpoints will also increase, reaching the mid to upper 50s. It may begin to feel a bit muggy by Saturday afternoon. In addition, chances for thunderstorms creep into the area. The general trend across multiple models has been an increase in the potential instability across the region. Couple this with moderate to steep lapse rates, and roughly 30 kts of 0-6 km bulk shear and the potential is there for strong to severe thunderstorms Saturday evening into Sunday morning.

Storms clear out for Sunday afternoon and most of Monday. Highs will climb to the 70s and 80s Sunday, slightly cooler in the 70s for Monday. Monday evening storm chances return again, and continue periodically through the first half of next week as the previously mentioned upper trough begins to move out over the central United States. At this time it is too early to say for certain when or where or if storms will become severe. But the potential is there beginning this weekend and continuing into next week. This increase in thunderstorm activity is typical for April in the Midwest. It's important that you know how to respond should severe weather approach your area. Know where the nearest shelter is located. Have multiple ways to receive warnings, especially at night have at least one method that will wake you up! If you have outdoor plans be sure to monitor the forecast closely for updates.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1233 AM CDT Thu Apr 9 2026

VFR conditions are expected for the TAF period. Light northwest winds persist late this evening. Expect winds to turn out of the northeast during the afternoon hours tomorrow with speeds increasing up to 5 to 15 knots. Chances for light rain showers will increase throughout the day, especially for the afternoon hours. A stray rumble of thunder is possible in the showers but confidence is not high enough to include in a TAF. Ceilings are expected to remain VFR in falling rain with perhaps a brief drop to MVFR visibilities possible. Rain will be ending across the area tomorrow evening to finish out the period.

FSD WATCHES/WARNINGS/ADVISORIES

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