textproduct: Aberdeen

KEY MESSAGES

- A Slight Risk (Level 2 of 5) has been issued for storms that are expected to organize across central/north central South Dakota during this evening, and then spread rapidly east to southeast through the overnight hours. Large hail (1 to 2 inches) and winds in excess of 60-70 mph are possible with these storms.

UPDATE

Issued at 614 AM CDT Mon Aug 10 2026

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

DISCUSSION

Issued at 1247 AM CDT Mon Aug 10 2026

Northwest flow with a weak trough passage across the state during the early morning hours. Just a weak low level jet across the area at about 20kts. Given the rather nebulous setup for weak forcing aloft and at the surface, CAMS are likewise struggling to come up with a unified solution and thus will maintain a rather low chance for POPs through the early morning hours. NAM BUFKIT profiles aren't even that unstable with minimal mid level CAPE. Then again, we remain in this northwest flow regime with a unidirectional shear environment so can't rule out a stronger storm or two but the overall prognosis is for mainly sub-severe type storms and isolated coverage.

Shift to this evening with a low pressure system developing out west and an inverted trough extending up across northeast South Dakota. A weak wave arrives late in the day, supporting convection in southeasterly low level flow with westerly unidirectional flow aloft. CAMS for the most part organize into a complex that drives across central/north central South Dakota in the evening/early overnight with an overall rapid progression east southeast across the state. HREF 0-3km helicity peaks around 300m2/s2 and the 4-hour max ensemble winds indicate 60+ kt potential with ensembles highlighting central South Dakota.

In regards to smoke, no real change. The Pacific Northwest and British Columbia continue to generate a broad expanse of thick smoke aloft which will continue to track across the region until we get a pattern change. Flow around the current surface high even as it moves off to the east currently has no low level smoke to advect into the area. The one impact smoke is most likely to have is influence on high temperatures. While I'll stick with NBM highs, realize that initial surface based thunderstorm intensity is contingent on temperatures and if the expected thick sheen of smoke knocks down temperatures 2-4F then the resulting convective evolution may not stick to the current CAM consensus.

The only major change to the pattern and forecast for the next few days is a much cooler airmass coming in for the latter half of the work week, as we see an eastern Canadian upper low strengthen, with a broad high across central Canada which dribbles slightly cooler air into the Northern Plains.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 614 AM CDT Mon Aug 10 2026

Terminals KABR,KATY,KPIR,KMBG

Got some MVFR/IFR stratus over portions of central/western South Dakota this morning in the low level upslope flow. KPIR/KMBG are VFR for now, but may be impacted at some point during the first few hours of the TAF valid period. Will monitor and update as needed. Otherwise, VFR conditions are forecast for all terminals through tonight. Hi-Res guidance supports a dry period through ~23Z before the next round of (potentially strong to severe) storms gets going by early this evening over the western Dakotas. Storms that develop are progged to shift over through and east of the Missouri River valley region (KPIR/KMBG) between ~03Z and 06Z Tuesday. Large hail 1-2+inches in diameter and thunderstorm wind gusts to 55 knots are possible.

ABR WATCHES/WARNINGS/ADVISORIES

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