textproduct: Aberdeen

KEY MESSAGES

- Low chances, 10-20%, for an isolated shower or storm to develop this evening into Thursday morning.

- There is a Slight (level 2 of 5) to a Marginal (level 1 of 5) risk for severe storms to develop over northeastern SD and west central MN late Thursday afternoon into the nighttime. The primary threats will be hail up to 2 inches in diameter and wind gusts of 60 to 75 mph.

- Above normal temperatures (5 to 15 degrees) continue through the week, peaking at 10 to 20 degrees above normal Friday and Saturday.

UPDATE

Issued at 638 AM CDT Wed Sep 2 2026

See below for an aviation forecast discussion for the 12Z TAFs.

DISCUSSION

Issued at 128 AM CDT Wed Sep 2 2026

As of 1 am CDT, there are some lingering showers over portions of northeastern SD and west central MN. These showers will be dissipating and moving out into the early morning. Other than the lingering showers this morning, there could be some localized areas of patchy fog. The easterly flow this morning could create upslope fog where the flow tries to move up over the terrain in areas of higher humidity. This fog will dissipate during the morning once the sun rises and the atmosphere starts to mix things up.

The moisture will be sticking around, as relative humidity values will stay above 55 percent for most of central and northeastern SD and west central MN today. This moisture as well as some higher instability, between 1000-2000 J/kg possible late this afternoon into the evening, will help to create a decent environment for storm and shower development. The one thing that will be lacking is a source of lift. Some models show a shortwave moving over SD late this evening and overnight, which would help with the development as a source of lift. However, there is variability in the models with the shortwave, as some of them don't have it moving over until Thursday evening and other models don't have any shortwave move over. Without the shortwave as a source of lift, the showers and storms will struggle to develop. There is also variability in the models as to how long the storms will be able to last if they do form. This is because some of the models hint at a low level jet developing overnight to support the showers and storms, while other models don't have the jet develop and the storms don't last. If things line up just right, there could be some isolated showers and storms late this evening and overnight into early Thursday morning. Models show lapse rates between 6-7 C/km and bulk shear up around 35 kts, which could help with some hail development and occasional strong wind gust tonight if the storms are able to happen, though there is lower confidence in this happening.

Southerly flow Thursday will help to warm the temperatures to be in the mid 80s into the low 90s, which is 10-15 degrees warmer than normal. These southerly winds will also help to push moist air into central and northeastern SD and west central MN. A frontal boundary is forecast to move through SD Thursday and overnight, which will help to provide the lift needed for storms and showers to develop in the moist environment. The models show the instability developing through the day mainly over eastern SD and west central MN, which is in front of the frontal boundary, with CAPE values of 1000-3000 J/kg. Depending on how fast or slow the boundary moves into and through SD during the day, there could be a smaller or larger area with chances for showers and storms to develop. The NAM shows some higher mid-level lapse rates between 6-7 C/km and bulk shear of 30- 45 kts, which could help with the development of some hail and stronger winds if anything were to develop. There does not look to be the development of a low level jet Thursday night, which might also limit the ability for the storms to stay alive through the night. There is a Slight (level 2 of 5) to a Marginal (level 1 of 5) risk for these storms to become severe. The primary threats initially look to be hail up to 2 inches in diameter and wind gusts of 60 to 75 mph. As the evening progresses, the storms will likely transition to more of a wind threat as they could become more linear.

After Thursday, an upper-level ridge looks to build over and slightly to the east of SD. This will help warm air to build in Friday and Saturday, causing temperatures to be 10-20 degrees warmer than normal. High temperatures Friday and Saturday are forecast to be in the upper 80s to mid 90s, warmest over central SD. The ridge should also help to keep showers and storm from developing, though some models have a shortwave pushing through Friday night into Saturday morning, which could support an isolated shower/storm or two to developing.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 638 AM CDT Wed Sep 2 2026

Terminals KABR,KATY,KPIR,KMBG

There are scattered/numerous showers, with some embedded thunder at/in vicinity of the KABR/KATY terminals right now. By 14Z, precipitation should be clear of these terminals, with all four terminals then expected to be dry for the rest of the TAF valid period. KPIR is experiencing some (MVFR) low clouds right now on a light east-component wind. These low clouds are seen expanding across portions of western/northern South Dakota, and could potentially impact the KMBG terminal for a few hours this morning. Beyond that, VFR conditions are forecast at all four terminals throughout the TAF valid period.

ABR WATCHES/WARNINGS/ADVISORIES

SD...None. MN...None.