Thunderstorms: On any day, the Earth may be host to 1,800 thunderstorms at once. Though each one may cover only a few square miles, thunderstorms are often dangerous. They can produce lightning, hail tornados, and floods. Thunderstorms are set off by updrafts of warm air carrying water vapor. As the rising air cools, the vapor condenses and falls as rain.
Lightning: Storm clouds can build up electrical charges as water and ice droplets tumble about inside. When the electrical charge is great enough, a bolt of lightning - electricity discharging - jumps between clouds or between a cloud and the ground. During lightning storms, stay inside, away from windows, and don't use the telephone.
Tornados: 'Twisters' are powerful rotating winds. Most often they grow out of thunderstorms. When warm, moist air collides with cool, dry air, a huge updraft can result, creating a tornado. The funnel-shaped trunk that drops down from a thundercloud may whirl at a deadly 300 mph, destroying everything in its path. Scientists know when conditions are ripe for tornados to form. However, even with top technology, forecasters can predict only about 20 minutes ahead of time where a tornado is likely to hit. During a tornado warning, try to stay indoors under a stairway, mattress, or heavy furniture.
Hail: Ice crystals tossed around in clouds by updrafts can form hailstones. As the crystals pick up more moisture, these ice balls grow. If they become so heavy the air currents can't hold them up, hail will fall.
Forecasters look at these basics: clouds, temperature, humidity, air pressure, wind direction and sky conditions. This ever-changing is is the crystal ball of weather forecasting. With the essential of how weather works that we described above, you're on your way to predicting our Earth's weather!
