September Already?

Wow, did this Summer fly by or what? Here we are at Labor Day already! Well, storm chasers actually look forward to this time of year. There is something called the "Fall Max" which is a return of some moderately severe weather to the Great Plains. I'll explain why we have another few weeks of severe thunderstorm potential in the Fall. Most severe weather is due to interaction with the Jet Stream, which is a ribbon of fast-moving air that circles the Earth at high altitude. The Jet Stream is formed along the border of cold, Canadian air to the north and warm tropical or continental air to the south. In between these two differing air masses, we find the Jet Stream, which is also called the Polar Front. During the Summer, the Polar Front is pushed far to the north as air from the tropics moves northward. In the winter, the Polar Front is usually positioned across the southern US. Most of the country is under the influence of cold, polar air. When Spring arrives, the Front begins to move northward. As this boundary between cold and warm air moves over the Gulf States, the interactions of cold and warm air, plus the high upper-level winds along the Front help to generate severe thunderstorms across the Southern Plains. As the Polar Front moves north with the return of warm weather, severe thunderstorms break out in the Central Plains, and then later in the Summer, over the Northern Plains. The Fall Max occurs as the Polar Front begins its southern trek with the return of Fall months. This means the chance of severe weather increases again from north to south. So, storm chasers get a last taste of the kind of weather we seek before the cold snows of Winter move in. As a matter of fact, October is one of Denver's biggest hail months! ~Steve.