Summer Storms Bring More Heavy Rain and Wind this Time of Year

Severe thunderstorms plowed through parts of the Upper Midwest this past weekend producing quite a bit of wind damage and over 10 reported tornadoes in northern Wisconsin. While tornadoes do occur this time of year, damaging winds and heavy rainfall actually become more common for the Stateline during the late summer months.

This has to do with how the jet stream works. The jet stream moves with the changing seasons, lifting north during the Summer months and shifting south during the Winter months. The winds that make up the jet stream are typically stronger during the transition months of Spring and Fall, as our seasons change. It's usually during that time that big severe weather outbreaks can occur, including tornadoes. But during the Summer months the jet stream winds weaken as it shifts into the northern Plains and in Canada. The weaker winds allow for slower moving storm systems, producing more heavy rain events. Also, we tend to get more nighttime thunderstorms this time of year (complex of storm systems) that follow the outer edge of the heat, feeding off of the energy and instability as well as the increasing wind from the low level jet. Those types of storms often carry more of a wind threat than they do tornado threat - although sometimes tornadoes can occur.

A second tornado season tends to peak during late October and November as the jet stream begins to shift south before the Winter season begins.