textproduct: Aberdeen

KEY MESSAGES

- A dangerous and prolonged heat wave will persist through the end of the week with temperatures and heat index values topping out in the 90s to low 100s each afternoon.

- A Heat Advisory remains in effect for north central, central, and portions of northeastern SD and west central MN through Thursday evening.

- Elevated fire weather conditions will be possible across West River zones this afternoon and Thursday as gusty winds of 25-30 mph develop anand minimum relative humidity values fall to between 20-25 percent.

DISCUSSION

Issued at 156 PM CDT Wed Jul 15 2026

Upper-level ridge over the region will persist over the next few days, continuing the above normal temperatures across the forecast area. The Heat Advisory remains in effect through Thursday for all counties bar Clark, Codington, Hamlin, and Deuel. Despite many areas not expected to strictly hit Heat Advisory criteria of 100 degree apparent temperatures, the extended duration of 95-100 degree heat indices covering much of the forecast area is enough to warrant the Advisory. For this same reason however, it may become somewhat tricky to determine the appropriate end time for the Advisory. Criteria will remain somewhat borderline through the weekend, with apparent temperatures likely just below that 100 degree mark over the forecast area Friday through Sunday. Looking at Heat Risk, the probability of reaching Major Heat Risk Friday and Sunday will be generally between 40-70% across the forecast area, with a slight dip to around 30-50% on Saturday. For now, keeping the Advisory through just Thursday for now, but an extension will definitely be on the table with future forecasts.

This heat will also cause the potential for fire weather impacts, particularly for the next couple of days. Southerly to southeasterly flow for the next couple of days will gust up to 20 to 30 miles per hour this afternoon, and up to 25 miles per hour Thursday. The strongest winds both days are expected over north central South Dakota. This also happens to be the location of the expected lowest afternoon humidities, around 20 to 25 percent. Therefore due to this combination of low humidity and strong wind gusts, parts of central and north central South Dakota may see Moderate to High Grassland Fire Danger this afternoon and Thursday. Low humidity (20-30% at the lowest in the afternoon) will stick around over central and north central South Dakota through the weekend, which may create additional chances for some elevated fire weather concerns once again.

Signals point towards relief from the heat by next week as the upper- level ridge in place begins to break down. Ensemble clusters show a fair degree of consistency in seeing this breakdown begin Monday. Naturally this will lead to a cooling trend, and midweek temperatures look to return to near normal to perhaps even slightly below normal.

The most substantial chances for rain during the forecast period appears to be on Sunday night into Monday. As the ridge breaks down, strong flow aloft has the potential to sink down into the region. The bulk of the jet streak riding down the front of the ridge will remain to the north, but the question will be if the southern edge will progress far enough southward to support divergence aloft over part of the Aberdeen forecast area (likely northeastern South Dakota to western Minnesota). Looking at the tracks of the jet streak in mid-range ensembles, the GEFS and Canadian tend to show a more southerly track, bringing some of the stronger winds overhead. Conversely, the Euro supports a slightly slower breakdown to the ridge, and keeps the jet streak just to the north. At the moment, the environment does not appear overly favorable for severe weather should storms develop Sunday evening, but can't rule anything out at this point, especially with a cold front expected to track through.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1158 AM CDT Wed Jul 15 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are expected through the rest of today and through Thursday morning. Other than a few high clouds passing overhead and some fair weather cumulus this afternoon over parts of eastern South Dakota, skies should remain clear through the TAF period. Wind will remain out of the south to southeast through the TAF period as well. These winds may gust as high as 20 to 30 knots, with the strongest located over north central South Dakota this afternoon. Gusts around 20-25 knots may linger overnight tonight and through Thursday morning.

ABR WATCHES/WARNINGS/ADVISORIES

SD...Heat Advisory until 10 PM CDT /9 PM MDT/ Thursday for SDZ003>011-015>018-021-033>037-045-048-051. MN...Heat Advisory until 10 PM CDT Thursday for MNZ039-046.