There are many things that can cause the weather to be dangerous and one of these things is the air pressure. Air pressure happens when there is a force that is pushed on the air molecules in a certain area. Because of gravity, the earth pulls the air molecules towards the earth and these air molecules cause pressure to be on the earth.
When the air pressure changes, it can cause there to be strong and intense weather. Colder air is more dense than warmer air. When the warm air begins to rise, it goes through the colder air and this causes there to be low pressure.
Low pressure then can cause there to be more rain because the water vapors that are found in the warm air condense and they rise, and it cools the air. When this cooler air gets up into the sky, it spread out moor and it cools down so much that it starts to fall to the ground.
When cold air flows down to the ground, it makes the area have high pressure. High pressure helps to bring out the sun and it gives us clear skies and great weather.
When the air moves from one level to the other, it causes there to be wind.
Weather people, or meteorologists can measure the pressure in the air. To do this, they use a barometer. The barometer can show how the air pressure is and tell if there is going to be a storm or some other change in the weather.
When the wind gets colder, the air falls and causes the humid, warm air to go up. When there is little difference between the low pressure and high pressure of air, little wind flows. When there are large differences, this can cause there to be strong winds and storms.
When there is a lot of air movement, it can cause an electrical charge. This wind and electrical charge form a thunderstorm. When a thunderstorm comes, it usually is followed by rain, thunder and lightning. Sometimes, even hail forms during a thunderstorm.
When there is a storm that is spinning from a tropical ocean, it can become a hurricane. Hurricane happens when there is low pressure that gains in strength and size. During a hurricane, the wind can get up to 199 miles per hour.
When there is low pressure, it can cause there to be a thin, cloud that is funnel shaped. These clouds spin and are called tornadoes. Most tornados develop in a cumulonimbus cloud. A tornado can bring winds up to 310 miles per hour.