An isolated thunderstorm is a type of thunderstorm that affects a small area, usually covering only 10-20% of the forecasted area. These storms are also known as single-celled thunderstorms and are mostly vertical in structure, relatively short-lived, and usually do not produce violent weather at the ground. Isolated thunderstorms tend to occur where there are light winds that do not change dramatically with height and where there is abundant moisture at low and middle levels of the atmosphere. They are less likely to cause extreme weather on the ground, although there is still a possibility. During an isolated thunderstorm, rain is usually heavy but brief, and lightning is typically infrequent. Hail and tornadoes are not very likely to occur during isolated thunderstorms because they don’t last long enough to spawn any severe weather.