We are off on a voyage to western South Dakota and the Black Hills. It’s a part of the world that will be popular with tourists this time of year, so this may be an important forecast for some readers.
At 1152AM, MT, Rapid City was reporting a temperature of 80 degrees with a vigorous northerly flow. Gusts of over 30mph were being reported, and the sunny skies were allowing for the warm temperatures. Most of the forcing today in western South Dakota is surface driven, and the cyclonic circulation in the area was due to a lee trough becoming established over eastern Colorado.
An upper ridge will actually set up along the Front Range, but northwesterly flow off the Rockies in response to surface low pressure will be dirty, with isolated showers and thunderstorms erupting in the slightly destabilized air for each of the next two days. The storms won’t be fueled by much moisture, but warm temperatures and a slight twist to the atmosphere could lead to some violent storms tomorrow afternoon. The little wave will shift towards the Mississippi Valley by Wednesday, which will help cut off the flow of moisture into Rapid City, but not until after some heavy rain has fallen in the early morning hours.
Tomorrow – Isolated strong thunderstorms, High 78, Low 59
Wednesday – Heavy rain early, becoming mostly sunny, High 81, Low 57
TWC: Tomorrow – Isolated T-Storms High 80, Low 57
Wednesday – Isolated T-Storms High 75, Low 57
AW: Tomorrow – Partial sunshine with a thunderstorm in parts of the area; humid High 79, Low 58
Wednesday – Partial sunshine (early AM T-storms) High 81, Low 57
NWS: Tomorrow – A 30 percent chance of showers and thunderstorms after noon. Partly sunny High 79, Low 59
Wednesday – A 20 percent chance of showers and thunderstorms. Mostly sunny, High 78, Low 58
WB: Tomorrow – Mostly sunny. A 40 percent chance of showers and thunderstorms in the afternoon High 79, Low 58
Wednesday – Mostly sunny with a 20 percent chance of showers and thunderstorms High 78, Low 58
It might be stormy in western South Dakota, but we will be looking at discreet cells that won’t really encompass the entire area, so you might get that trip to Mount Rushmore in with no problems.