Thunderstorms are in the forecast. That usually means the air near the ground is warm and moisture laden, while the air aloft is pretty cold. Bring in a cold front and wham, you get a thunderstorm.
News 11 Meteorologist Mike Stone says the typical thunderstorm produces a brief period of heavy rain, and lasts an average of 30 minutes. While the thunder won't hurt you, lightning will. Other hazards can include hail, heavy rain, flooding, and strong winds.
According to the National Weather Service, a severe thunderstorm is when winds reach or exceed 57.5 miles per hour or produces dime-sized hail or larger.
Thunderstorms need three things to form: moisture, unstable air and lift. One begins to form when the warm, humid air rises up from the ground in an updraft. The air cools and condenses into clouds. When the condensation becomes heavy it falls as rain dragging "down" air forming downdrafts.
At this point -- the downdrafts and updrafts coexist making this the storm's most violent period. But eventually the downdrafts choke off the updrafts -- cutting off the storm's source of energy and bringing the storm to an end.
Out of the 100,000 thunderstorms that occur in the US each year, only 10%are severe thunderstorms. A typical thunderstorm is 15 miles in diameter and lasts for about 30 minutes.
Knowing basic terminology is the first step in staying safe in a thunderstorm:
Here are some safety tips for when a thunderstorm is approaching:
Lightning is one of the most dangerous parts of a thunderstorm. Here are some interesting facts to remember:
The other big killer in thunderstorms is flash flooding. The term "flood" refers to a long term event that is many times associated with general rains that last for several days. The rains eventually drain into rivers and streams and fill them with too much water. The flooding can actually develop after the rain has stopped.
The difference between a flood and a flash flood is that flash floods result from heavy, localized rainfall from slow moving thunderstorms. This often occurs around small creeks and streams that overflow during the heavy rainfall.
You may hear the terms "Flash Flood Watch" or "Flash Flood Warning," here is the difference:
There are several safety rules that you can incorporate into your severe weather plan when it comes to flash flooding:
Posted by AEB