When you hear the words scattered and isolated in a weather forecast, it doesn't necessarily mean that 30 to 50 percent of the area will get thunderstorms. It actually refers to the nature of the storms themselves and how they move. In other words, they are different types of thunderstorms that can occur on a given day, and they differ in their impact.
When a thunderstorm forms, it happens when there's an imbalance in the atmosphere caused by a cold front colliding with a warm front, a surface low or a large cloud called a cumulonimbus. In most cases, the warm air rises faster than normal and causes precipitation and strong winds. Thunderstorms often create flash floods that wash away cars, homes, public properties and stray animals. They also destroy crops and cause power outages and property damage.
A thunderstorm's characteristics are determined by its cloud base and the type of updraft that rises within it. When the updraft is weak, it may not last long, resulting in short-lived storm cells. These are also known as pulse storms. They typically have high wind speeds, low cloud bases and occur with vertical wind shear that is weak or moderate in intensity in the lowest five to seven kilometers of the troposphere.
Isolated thunderstorms are loners that concentrate on one particular place, while scattered thunderstorms cover a larger area. Those characteristics make them different from multicell cluster thunderstorms, which can be severe with small hail and weak tornadoes. Both types of thunderstorms can produce heavy rains, strong winds and lightning strikes. It's important to follow safety guidelines like avoiding outdoor activities when lightning is present, and taking cover in a building or vehicle if it's thundering.