Why does the Midwest experience strong storms?

Answer 1

There are several factors.

In the Midwest there are frequent collisions between warm, humid air from the Gulf of Mexico with cool air from Canada,dry air from the Rockies, or a combination of the two. The Gulf air provides ample energy for storms while the other air mass creates a weather front that triggers storm formation. At first, however, storm formation is held back by a layer of stable air called a cap, usually found about a mile above the ground. The air under the cap becomes increasingly unstable so that when storms break through, they will be even stronger than without the cap.

Finally there is wind shear, which can have several effects on thunderstorms. In a normal thunderstorm, rain-cooled air creates a downdraft that starts to choke off the updraft that feeds the storm. The cool air then rushes out ahead of the storm, forming an outflow boundary that cuts off the storm from its fuel supply. These processes limit how strong most storm can get and how long they can last. The right setup of wind shear can take away both of these limits. First, the wind shear can tilt the vertical air movements in a storm, creating separate updraft and downdraft areas so that the downdraft does not interfere with the updraft. Second, the wind shear can give a storm a forward push, allowing it to keep pace with its outflow boundary so that it is not cut off from its fuel source. Wind shear, there allows storms to become stronger and last longer. Finally, wind shear can create rotation within thunderstorms, which makes it possible for tornadoes to form.