Severe Thunderstorm Warning - a severe thunderstorm has actually been observed by spotters or indicated on radar, and is occurring or imminent in the warning area. Tornado Watch - conditions are conducive to the development of tornadoes in and close to the watch area. Tornado Warning - a tornado has actually been sighted by spotters or indicated on radar and occurring or imminent in the warning area. According to NOAA, lightning strikes the Earth 100 times each second . There are about 45,000 thunderstorms daily and 16 million annually around the world.
Lightning always accompanies the thunderstorm .
These are nature's warnings that the thunderstorm is in its most violent stage. Tornadoes may also be associated with the thunderstorm. Thunder is the sound produced by explosive expansion of air heated by a lightning strike. When lightning is close by, the thunder sounds like a sharp crack . This can be done by counting the number of seconds between the lightning and thunder and dividing by five.