textproduct: Aberdeen

KEY MESSAGES

- There is a Slight risk (level 2 of 5) for severe storms to develop late this afternoon across southwest South Dakota and migrating into south central South Dakota during the evening hours. Main threats include up to 1 inch in diameter hail and wind gusts of 60 to 70 mph.

- There is a Marginal risk (level 1 of 5) for severe storms to develop late this afternoon west river, migrating east in the evening and overnight. Main threats include up to 1 inch in diameter hail and wind gusts up to 60 mph.

UPDATE

Issued at 727 AM CDT Wed Aug 12 2026

Areas of locally dense fog have cropped up over portions of central and east central SD. The visibilities in this fog could drop to 1/4 mile at times. An SPS was issued for the next few hours because of the fog. This fog should dissipate through the morning, with the fog in east central SD already starting to decrease in strength.

UPDATE Issued at 610 AM CDT Wed Aug 12 2026

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

DISCUSSION

Issued at 1238 AM CDT Wed Aug 12 2026

The 4-Corners upper high weakens and shifts into the southeast CONUS, though we still remain under a broad west/northwest flow regime. A plume of mid level moisture lifting out of the intermountain west crosses South Dakota during the day. You can see this broad area of mid level clouds over Nevada/Utah Idaho/Wyoming. This moisture, 600mb and above, also has a very dry subcloud layer resulting inverted V type soundings. Profiles also have warm air aloft and while 700mb temperatures are only +8 to +11C which doesn't jump out as a strong CAP, 750mb temperature are closer to +13 to +15C so NAM profiles indicate it will be difficult for surface based convection but elevated convection is depicted in CAMS for the evening/overnight hours. HREF MUCAPE is only about 1500j/kg. Given the profiles, winds are the main concern with any convection. Given how dry its been, dry lighting and fires also are a concern.

There is another plume of mid level moisture for mainly Thursday night into early Friday as well. Profiles are close to moist adiabatic thanks to cooler mid level temperatures with easterly stable low level flow with the surface high just across the border in Canada. NAM BUFKIT profiles show its unstable during the day, though there is an upper ridge moving overhead with increasing heights at that particular time.

A southwest flow regime runs through Saturday before flow aloft becomes more westerly, and ultimately northwesterly for next week. NBM POPs have trended down this weekend and next weekend in response, especially as a surface high moves across the region Sunday/Monday. Otherwise temperatures with this cooler airmass will be running about 5 to 10 degrees below normal Thursday through Sunday.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 610 AM CDT Wed Aug 12 2026

Terminals KABR,KATY,KPIR,KMBG

Low stratus and fog (sub-VFR conditions) are developing again this morning, primarily over portions of central and north central South Dakota. VFR conditions are expected to be restored prior to 18Z today (KPIR and KMBG?), and VFR conditions are forecast for the rest of the TAF valid period.

Caveat: thunderstorms are possible by late this afternoon/early evening and will probably carry with them a sub-VFR visby in heavy rainfall. Thunderstorms into Wednesday evening/night could also produce strong wind gusts in excess of 50kts.

ABR WATCHES/WARNINGS/ADVISORIES

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