It s that time of year again when the residents along the Great Lakes Region prepare for their own version of hurricanes, otherwise known as Fresh Water Furies. In the fall, as the air rapidly cools and the first strong troughs of season cross the still relatively warm Great Lakes, very deep low pressure centers can form. As the air near the surface is warmed, the atmosphere over the Great Lakes becomes increasingly unstable.
Strong convection can develop, which adds heat energy to the atmosphere resulting in intense storms.
This pattern is similar to the way thunderstorms develop over the warm Gulf Stream causing explosive storm development and Nor'easters off the East Coast, and how strong convection over the very warm tropical waters provides the energy for tropical storms and hurricanes to develop. Over the Great Lakes Region this time of year, strong vertical currents in the unstable air help transfer higher speed air from aloft down to the surface, resulting in very strong wind gusts. The coupling of the wind and water in the unstable air also results in higher waves. This is in contrast to the late winter and spring, when the water is still cold and there may be snow or ice cover. During these seasons, the lower atmosphere is cooled and the air becomes more stable.