IOWA — We are jumping head first into summer for the unofficial start of the summer season! Memorial Day weekend will be a warm and humid across the state. Highs will rise above average to the 80s on Saturday and could even reach the 90 degree mark by Sunday.
An area of low pressure and warm front stretching across the Dakotas and Minnesota will lead to the development of a strong low level jet early on Saturday. This will increase dew points and humidity across our state, but the focusing mechanism for storms will stay further north in the Dakotas and Minnesota. Winds will be out of the south at 5-15 mph with some gusts over 30 mph. Temperatures will rise to the mid-80s.
Another push of warm reinforcing area builds in across Iowa Sunday. This will bring in more high level cirrus clouds which could impact day time highs with a range of mid-80s to 90 degrees. However, winds will still be strong with gusts over 30 mph out of the south-southwest.
The best storm chance in the region will be late Sunday night through Monday morning. A complex of storms looks to form in Nebraska late on Sunday and will move northeast, bringing strong winds and possibly large hail as it moves in the southeast South Dakota and western Minnesota. A few storms on the eastern edge of this complex could brush portions of northwest Iowa.
Monday will begin with some remaining clouds drifting over Iowa from the overnight complex of storms to the northwest. Clouds will clear out and temperatures will again be above average. This may cap the environment again and prevent storms from firing up during the day.
By late Monday night into Tuesday morning, a cold front will begin to move into western Iowa. Storm motion looks to be along the front south to north, so areas of heavy precipitation over the same locations may occur in western Iowa. A few of these storms in Western Iowa on Monday evening may become severe with large hail, damaging winds and an isolated tornado threat.
Tuesday, the front moves into Central Iowa and increases storm chances for Central Iowa both early in the day and again late afternoon and evening on Tuesday.