For Sunday in KELOLAND, clouds clearing out throughout the day with even warmer highs than Saturday. Highs around 90 in the southeast, mid-90s for the Aberdeen and Rapid City areas while central KELOLAND will top out in the upper 90s with a few areas hitting the triple digit mark. With the extra heat and humidity, there is a chance for some storms to pop up late in the afternoon in the eastern half of the state. These will be random in nature and because these are diurnally driven, they should fade out relatively quickly once the sun goes down.
Monday, the hottest day with areas in central KELOLAND reaching the 100 degree mark again. Everywhere else will top out in the mid to upper 90s. Because of the strong heat, the National Weather Service has issued a heat advisory for eastern KELOLAND that will go into effect Monday at 11AM CDT and is set to expire at 9PM CDT Monday evening. They are expecting heat index values to range from 100 to 105.
Monday late afternoon/evening, central and eastern South Dakota have a chance for some thunderstorms. The southerly winds all weekend bringing in more moisture on top of the extra heat energy from the day, some of these storms could be severe with high winds and large hail. The strong weather looks to be mostly in the northeast portions of the state.
These look to fade out by Tuesday morning, dry conditions for the rest of the week until Friday. Highs cooler in the low 80s to around 90 lasting throughout the week.