textproduct: Aberdeen

KEY MESSAGES

- There is a Slight (level 2 of 5) to Marginal (level 1 of 5) risk for severe storms to develop this afternoon west river, migrating east through the evening and overnight. Main threats include wind gusts of 60 to 70 mph and hail up to 1 inch in diameter. Additionally, heavy rainfall could lead to localized flooding in a few areas.

- Next chance for showers and storms will be Thursday night into Friday morning over central and northeastern SD. These storms are forecast to stay below severe criteria.

UPDATE

Issued at 911 PM CDT Wed Aug 12 2026

Largest area of moderate to heavy rainfall is over the northern CWA from Brown county westward towards MBG. Updated PoPs to reflect very high chances over this area. Severe storm threat for the remainder of the night is very low. Will watch for pockets of heavy rainfall in the next hour, mainly in Brown county and the Aberdeen vicinity where an inch+ is not out of the question.

UPDATE Issued at 622 PM CDT Wed Aug 12 2026

Updated PoPs across the region to better align with radar trends and be in better collaboration with neighbors. Continue to watch showers and embedded thunderstorms move slowly east across central SD and starting to approach the James River valley. A few cores spike up at times, but having trouble sustaining anything significant. Severe storms not out of the question, but overall threat seems somewhat low for anything larger than quarter inch hail and 60 mph gusts or greater. Could see a couple isolated cases of this though. Will continue to monitor trends through the evening.

DISCUSSION

Issued at 130 PM CDT Wed Aug 12 2026

Wildfire smoke will continue to move in today. While most of this smoke will stay above the surface, portions of northeastern SD could see some of this smoke get to the surface. The concentration of smoke will not be enough to cause a decrease in visibilities, though the air quality will drop into the moderate Air Quality Index category. Those who are sensitive to air pollutants could be impacted slightly. Temperatures today are on track to be around normal, with highs in the 80s.

As a weak upper-level shortwave moves over SD this afternoon into the evening, a surface boundary will be moving into central and northeastern SD. This shortwave and surface boundary will help to provide some forcing for shower and storm development today as they move over an area with some instability. The models are showing CAPE values of 1000-2000 J/kg over central and portions of northeast SD this afternoon into the evening, decreasing as the surface boundary moves in. Mid-level flow from the intermountain west will help to move in moisture in the mid-levels and create a bit of an inverted-V sounding. The inverted-V sounding indicates 2 things: that the convection will likely be elevated, and that strong winds from microbursts will be possible in the storms. There is a slight (level 2 of 5) to marginal (level 1 of 5) risk that any storms that develops could become severe, with the highest risk for severe storms over south central SD. The main hazard will be strong wind gusts of 60-70 mph. Even though there will be weaker lapse rates, if any isolated cell does develop in front of the boundary, there is a risk for hail up around 1 inch. Additionally, with the moisture moving in from the intermountain west helping to feed the storms, there could be heavy rainfall at times. If multiple cells were to move over the same area, that rainfall could add up and create localized flooding at times. These storms should move out of central and northeastern SD during the early overnight hours, with the potential for a few lingering showers into early Thursday morning.

Behind the surface boundary, cooler air will be moving in Thursday. This will cause temperatures to fall slightly, to be about 5 to 10 degrees below normal through the weekend. High temperatures will be in the 70s during this time. There is a little bit of variability in the models as to precipitation chances Thursday. Some models keep some isolated showers and storms over central and northeastern SD Thursday morning and afternoon, while other models keep the showers and storms out of the area. The next larger chance for showers and storms to move in will be Thursday night into Friday as the Lee of the Rockies surface trough starts to move over and through SD. Models show very weak instability over northeastern and central SD as well as weak lapse rates and shear. Because of this, these showers and storms will likely stay as weak storms with little chance to become severe.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 622 PM CDT Wed Aug 12 2026

Terminals KABR,KATY,KPIR,KMBG

SHRA/TSRA continue to move eastward across the region, with all TAF sites likely affected at some point this evening/tonight. Heavier downpours that manage to move over a TAF site could bring brief MVFR/IFR VSBY. Potential also exists for areas of MVFR/IFR CIGs across the region as well, especially in the wake of this system late tonight into Thursday morning.

ABR WATCHES/WARNINGS/ADVISORIES

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