SIOUX FALLS, SOUTH DAKOTA — A Level 2 slight risk of severe weather has been outlined for central and eastern South Dakota into southwestern Minnesota for Tuesday, July 7. Forecasters say pre-frontal heating combined with deep moisture and steep lapse rates will drive destabilization throughout the day, setting the stage for thunderstorm development in the early evening hours.
Slight Risk Zone Centers on Sioux Falls and Rapid City
The Level 2 slight risk zone stretches across a corridor including Sioux Falls and extending northwest toward Rapid City, with the surrounding marginal risk area reaching into Minneapolis, Omaha, and Lincoln. This setup closely mirrors Monday’s severe weather event that impacted North Dakota, with a similar capping air mass expected to suppress southward through the day.
Once the cap breaks down, forecasters expect thunderstorm development sometime during the early evening hours, with the primary threats being severe hail and damaging wind.
Strengthening Jet Stream To Fuel Overnight Supercells
A strengthening low-level jet during the overnight hours is expected to support the growth of initial discrete supercells, which are forecast to grow upscale into a more organized convective system as the night progresses. This organized complex will carry the primary severe hail and wind threat as it initially develops.
Forecasters note that this evolution from discrete supercells into a broader complex is a hallmark of nocturnal severe weather events across the Plains, often intensifying wind threats as the system consolidates overnight.
Damaging Wind Threat To Increase Overnight Into Wednesday
As the storm complex travels east-southeastward through Tuesday night, forecasters say it will pose an increasing threat for damaging wind gusts across the middle Missouri Valley and into the Upper Midwest. This means areas including Des Moines and the broader Minneapolis region could see impacts as the system tracks through overnight…