textproduct: Aberdeen

KEY MESSAGES

- Marginal Risk (level 1 of 5) for severe storms this afternoon and evening. Main threat include wind gusts of 60 to 70 mph, especially in north central South Dakota, along with quarter size hail. The storms are expected to diminish in intensity as they move east from north central South Dakota in the evening.

- Temperatures will remain 5-7 degrees above normal (80s to lower 90s) through much of next week.

UPDATE

Issued at 208 AM CDT Sun Aug 30 2026

Update to the key messages to remove the early morning severe threat.

DISCUSSION

Issued at 1248 AM CDT Sun Aug 30 2026

As of 1230am, there is an impressive supercell moving eastward into Potter/Sully county, which is located along the northwest side of the 850mb warm air advection that stretches from there and to the southeast towards southeastern SD. There were other cells that developed along the WAA to the southeast of this main storm, but they've since dissipated, but do have other storms to the northwest of this one which are associated with a shortwave noted on WV imagery. With the forcing likely to continue to push slowly to the east-northeast through the night and plenty of instability (2k J/kg) and shear (40-50kts), not too much to inhibit this storm from continuing to the east tonight and will likely come down to storm scale processes over the coming hours. The rest of the convection in north central SD will lift to the northeast with time this morning.

Behind the early this morning elevated convection, will continue to see a broad surface low over South Dakota through the day. One of the main questions for the eastern part of the area is where the warm front and associated WAA will settle through the day, as this could lead to some development farther east this afternoon than the primary threat that will be moving through the north central part of SD. This area along the warm front will have ample instability (1500- 2500 J/kg of MUCAPE) and shear (40kts), with continued elongated hodographs leading to the potential for an isolated supercell. Of course, anything occurring right along the warm front could lead to a brief tornado threat too. Now for the primary potential for convection this afternoon and evening. The upper low near WA/ID/MT/Canada border area will move to the east-northeast through the day today and into southern Saskatchewan by this evening. The falling heights and cooling temperatures aloft will be strongest to the northwest of the area and lead to the convection developing upstream and along the cold front moving easterly through MT/WY this afternoon. As the storms move eastward this evening and into the Dakotas (and some likely developing out ahead of the front), they'll encounter increasing instability (going from 500-1000 J/kg to 1000- 2000 J/kg) as they move into western ND and northern SD. The combination of the forcing and the increase in instability expect both an increase in coverage (towards linear mode) and a continued potential for severe storms. This will likely lead to the severe threat shifting from hail/wind to more wind threat with time. Expect the severe threat to be focused in north central SD and northward, with the primary questions being how far south and to the east it will go. It will either be fighting less forcing (farther south option) or increase in nocturnal inversion (farther east). CAMS in general are fairly consistent in a limitation in the southward extent (generally north of US-212), but vary in the eastward extent (some dying things in north central SD and others moving it into north central SD). So will need to continue to fine tune the expectations through the day today.

The upper level and surface low will continue to the northeast on Monday, allowing high pressure to build into the region. Expect the tight pressure gradient over eastern SD to diminish quickly Monday morning and winds will be light over the area under the high for the rest of Monday. Slightly cooler temps will be in place for Monday, although still being around or slightly above normal (low-mid 80s). Drier air will also move in, with dewpoints falling into the low-mid 50s, so will be a pretty nice and comfortable day. That may change going into Tuesday, as a shortwave rounds and exits the upper trough off the west coast and moves through the northern/central Plains. There does appear to be a more northerly shift to this wave and the resultant surface features (elongated surface low from somewhere between southeast SD and southeast NE), leading to an increase in the precipitation chances compared to 24hrs ago (now 40-60% vs ~20% 24hrs ago). There is the potential for some heavy rain with this wave, as NBM 90th percentile 24hr QPF amounts are in the 1-2" range (75th percentile is 0.25-1"), with the highest amounts over the southeast half of the CWA. As for severe, ML output does hint at some lower probabilities of severe weather with this wave (ensembles have 1-2k J/kg of CAPE and 30-40kts of shear), so will need to monitor that potential over the coming days.

Behind that wave, the upper ridge will build over the north central CONUS, although there still continues to be uncertainty on the ridge axis. Latest trends are for it to be around MN and amplifies through the end of the week. That will lead to temperatures warming into the mid-upper 80s to low 90s across the area. At this time, not too much for signals for precipitation for the second half of next week and into next weekend, as the amplification of the ridge likely keeps much of the shortwave tracks to the northwest of the area.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1220 AM CDT Sun Aug 30 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast to prevail through the next 24 hours. For the rest of the overnight, scattered TSRA/SHRA are expected to move across the KMBG terminal periodically. Otherwise, dry conditions are forecast until Sunday evening when the next round of TSRA/SHRA may develop over the region. Again, KMBG and perhaps KABR hold the highest probability of experiencing precipitation. Any TSRA/SHRA that moves over a TAF site is capable of brief MVFR/IFR VSBY.

ABR WATCHES/WARNINGS/ADVISORIES

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