• There are different reasons for the rising of moist warm air.  One is when the heat on or near the ground varies, usually at the fronts.  Also occurring at fronts is the verging of two different amounts of moisture.  Again the warmest moist air rises.

http://www.srh.weather.gov/jetstream/tstorms/ingredient.htm

There are two types of thunderstorms:  Single Cell and Multi-Cell

Single Cell

These storms are also called “pulse” thunderstorms.  They are very short.  However, there is a special kind of single cell thunderstorm that is very dangerous and produces most of the tornadoes occurring each year bringing along with it golf ball size hail, extreme winds, and flash flooding called Supercells.  They are created by a strong rotating updraft of wind increasing in speed as it rises.  Low Precipitation supercells have little rain or hail and High Precipitation supercells have a lot of rain or hail.

Multi-Cell

These thunderstorms contain several single cell thunderstorms.  The single cell storms converge when they are at different stages in their cycle.  When one ends a new one may be beginning.  A majority of the time these storms follow the same path creating a “Squall Line”.  These can go on for hours creating storms after storms with each others leftovers.

http://www.srh.weather.gov/jetstream/tstorms/tstrmtypes.htm

To tell how far away a thunderstorm is just count the number of seconds after you see lightning till the thunder.  Take that and divide by five.  That gives you how many miles away the storm is.

There are approximately 1,800 thunderstorms occurring across the earth each day.  Most thunderstorms in the US occur at the Southeastern part.  Florida averages more than 100 thunderstorm days per year, twice as much as the Midwest!

http://www.srh.weather.gov/jetstream/tstorms/tstorms_intro.htm