Source: NOAA and NWS
Why a resurgence in tornado potential in the fall months? It all has to do with a combination of fast Jet Stream winds and strong frontal systems which reappear in fall. During the late summer months thunderstorms are common, but winds throughout the atmosphere rarely are strong enough to allow tornadoes to form. During the spring and Fall however, a strong gradient of temperatures across the hemisphere typically drives powerful Jet Stream winds, and creates much stronger frontal systems which help initiate thunderstorm development.
It's the time when temperatures begin to get a little cooler (or at least they will), but it's also the season for severe weather. Although our region seems to be fair game for storms almost all year, the fall is a secondary peak of severe weather for the Local 6 region. That's one reason the National Weather Service calls the week of September 20th Fall Severe Weather Awareness Week, for much of the viewing area. Now is the time to make sure you review or create your safety plan(s), brush up on weather terminology and get those weather radios in good working order.
Here are a few things to help you get prepared for the season:
Severe Weather Terms:
A WATCH means conditions are favorable for severe weather. While there may not be any storms in the area, some may develop and become severe. Watches are usually issued for large areas (generally covering a state or two) and for several hours.
A WARNING means severe weather is already occuring in part of the warned area or is likely to very soon. These are usually issued for about an hour or less, and a much smaller area than a watch.
In the case of a SEVERE THUNDERSTORM WARNING, it means a storm may produce winds of at least 58 mph and/or hail of at least 1" in diameter.
A TORNADO WARNING means either National Weather Service radar has indicated rotation or trained spotters have reported a tornado.
Have a Plan
Before severe weather takes aim on your area, get a plan in place. This includes putting together a survival kit. It's better to be prepared and not need it, than to wish you had it and be too late. Make sure you and your family know the safe places to go and where to meet, after the storm moves through. The safest place, during any storm, is an interior room on the lowest level of a sturdy structure.
Source: NOAA and NWS