In the upper levels of the atmosphere, a slow moving trough of low pressure is moving over the Midwest, and it’s bringing KELOLAND passing rain and storm chances this weekend. At the surface, a weak frontal boundary will slowly move west to east through the area the rest of today through tomorrow. Along and ahead of this boundary, we’ll have chances for showers and some rumbles of thunder. Then a cold front will swing through Sunday into Monday, and that will bring passing thunderstorms to parts of central and east KELOLAND Sunday afternoon into Sunday night. Next week, the upper level flow should remain out of the northwest which puts us at risk of quick hits of light rain and cooler temps.
Light rain will keep trying to move in from the south tonight as well as rain or thundershowers popping up along the frontal boundary that is moving in from the west, so central and east KELOLAND have the greatest chance to see spotty rain after Midnight. West SD will likely see clear to mostly clear skies. Overnight temperatures will fall to the 60s.
Sunday will be cloudy to mostly cloudy in central and east South Dakota with some light to moderate rain falling out of those clouds, but late Sunday is when strong thunderstorms and heavy rain is expected due to the passing cold front. Sunday’s afternoon temps will be in the mid 70s to 80s. The wind will be out of the south, until the cold front passes through later in the day, then the wind will swing around to the north.
There is a possibility for severe weather with the best chances in in central SD with a marginal risk in the east and west. If storm cells are able to strengthen to severe status, strong wind gusts and large hail will be the main threats.
One aspect of this forecast that is looking good is a good portion of KELOLAND could end up with some decent rainfall. At this point, central and northern KELOLAND has about a 60 to 80% chance at getting more than a half an inch of rain through Monday morning. The northern counties in South Dakota still have about a 40 to 50% chance of seeing more than an inch of rain. So through Monday morning, most rain amounts will probably range between a quarter and three-quarters of an inch, with some of the higher end reports getting an inch or more.
The rain looks to continue into Monday but mainly during the morning hours and in east KELOLAND. The afternoon will see decreasing clouds and mostly sunny skies. Temperatures will be a little cooler, in the mid to upper 70s.
Next week is looking dry overall but that being said, that northwest flow in the upper parts of the atmosphere puts us at risk of quick moving hits of light rain so stay plugged into the forecast and don’t be surprised if those quick hits end up being added to the forecast. Highs next week are looking well below normal as they are projected to be in the 70s for most of the area, some counties in the northeast may struggle to get out of the 60s some days late next week!
It looks like temperatures will remain in the 70s, slightly below normal, through the Labor Day weekend.