When reading a weather forecast it can be confusing to know what the words isolated, scattered and widespread mean. One of the most confusing is isolated showers and thunderstorms. When this phrase appears in the weather forecast it means that less than 20 percent of a county or viewing area is expected to experience rain or storms at any given time. Isolated storms can also cause heavy rainfall and strong winds.
When a meteorologist talks about isolated showers and thunderstorms, they are referring to the likelihood of measurable precipitation over the forecast period, which is usually 12 hours. This is similar to the “20 percent chance of rain” style of forecast that we are all used to seeing.
In this case, the term isolated means that the storms will not be associated with a front and will likely develop by themselves. Because of this, they are hit or miss and it is possible that a few square miles will have an active storm while the surrounding area remains dry. This can be very difficult to predict and it is best to stay indoors when these conditions exist.
When isolated thunderstorms are forecast, it is important to keep an eye on the sky. If you do go outside, be sure to remove any outdoor furniture or other items that could blow away in the wind and to keep an eye out for lightning. It is also a good idea to unplug any electrical items and to remain inside when the storms arrive.