Ever wonder why some nearby locations are hit hard by thunderstorms and others miss out on much needed rain in the summer? We will try to explain the randomness in this story.

Your typical, garden variety, summer thunderstorm may only span a few square miles. Quite often the sweet spot with downpours, frequent lightning and hail is much smaller.

If you are on the edge of the storm, you may only get a brief gust of wind and no rain.

To get a thunderstorm to form you need rising air, which then cools and forms the cloud. You need heating of the ground to get rising air. Most thunderstorms in the summer thrive during the hours from 3:00 p.m. to 9:00 p.m. when the air is rising the most, from the heating of the day.

Think of a thunderstorm as a moving skyscraper. The clouds shoot miles into the atmosphere, due to updrafts. However, since air is going up in the towering cloud, it has to go down somewhere, and that usually occurs on the perimeter of the storm.

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If you are right under the tower, you have a good chance for getting slammed. If you are on the edge, it is like hearing the kids play a video game in another room.

Typical airmass thunderstorms often form along ridges and tend to move along the ridges or even jump from ridge to ridge. This is because the mountains represent a high-level heat source in which where air is rising more vigorously, as opposed to valley locations.

Thunderstorms also tend to form on the edges of cloudy and sunny areas, as well as warm and cool locations, such as along a sea breeze boundary. Meteorologists refer this as differential heating.

Sometimes even a ring of cool air put down by last evening's thunderstorm can contribute to a new storm the following day! This is a common occurrence in the southern U.S.

Weak disturbances or fronts can also contribute to random thunderstorm formation in the summer. After all, these phenomena represent broad areas of rising air.

While thunderstorms in these situations are often more organized, the same rules apply concerning differential heating and geography affecting their severity at one location verses the next. Just because a front is approaching, does not mean you are guaranteed of getting rain from it.

When you factor in all of these known physical characteristics of thunderstorm formation, you wind up with a fairly unpredictable situation as to which neighborhoods will be hit and which ones will be missed by thunderstorms on a given day.

Days in advance, AccuWeather.com meteorologists prepare outline general areas where thunderstorms will hit along with their severity and characteristics, such as tornadoes versus straight-line winds.

The local nature of the thunderstorms can still play havoc. In addition, thunderstorms go through multiple strengthening and weakening stages during their life, which are nearly impossible to predict and can have tremendous effects at the local level.

If you have outdoor plans, utilize our forecasts and weather stories and videos in advance here at AccuWeather.com. Next keep an eye on AccuWeather.com radars, expert commentary and warnings as the hours and minutes draw near to your event.

Summertime thunderstorms will continue to maintain the element of surprise even in the best forecast because of the dozens of local factors affecting the storm intensity and track, which can change by the minute.

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