The National Weather Service in Sioux Falls have issued a new Severe Thunderstorm Warning for Plymouth and Sioux Counties in northwest Iowa. This new warning will remain in effect until 12:45pm. A severe thunderstorm moving into Iowa has a long history of producing extremely large hail up to 3.00” in diameter. That’s bigger than tennis balls. The storm is accelerating a bit, moving to the northeast at 40mph.
One other thing to watch our for with this storm. Trained spotters in South Dakota spotted a wall cloud within this storm a short while ago, prompting a tornado warning. We’ll monitor that threat, but for now the primary threat is dangerously large hail and some strong wind gusts.