When cumulus clouds associated with good weather meet rising warm air, chaos occurs. They form cumulonimbus clouds that produce heavy rain, thunder, lightning, hail, and strong winds.
The sky will often have a dark gray or black appearance.
These storms occur quickly and can last from 10 to 20 minutes in length.
Every thunderstorm has a mature cycle and dissipating cycle during the storm. There are several different types of thunderstorms.
They are single cell, a multi-cell cluster, multi-cell squall line, and supercells. Thunderstorms need moisture, weather instability, and a force that causes them to occur.
About 100,000 thunderstorms occur in the United States every year.
Scientists have calculated that about 760 storms occur every hour all over the earth and 1,800 storms daily.
Cumulonimbus or nimbus clouds are the only clouds that produce thunderstorms with hail, lightning, and thunder. They form in warm weather, warm air creates clouds that are 20,000 feet or more in size. Cold and warm air collides, causing rain, thunder, lightning, hail, and sometimes severe storms like tornados.
It begins when a cumulus cloud meets warm air and begins to form a storm cloud called cumulonimbus. The first factor that fuels thunderstorms are moisture that comes from large bodies of water, large areas of plants or vegetation, and irrigated areas of land.
The dewpoint should be above 50-55 degrees Fahrenheit. The next cause is instability in the atmosphere when some sections of air are cooler and others warmer. The air collides, causing instability in the atmosphere.
The final factor is lift caused by sea breezes, cold or warm fronts, rising air, mountains, and bodies of water. Sometimes, when the wind increases, this causes thunderstorms to last longer in duration.
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What Causes a Thunderstorm?
There are several types of thunderstorms. Ordinary cell or pulse thunderstorms are short storms that have wind and hail. They are caused by an updraft and downdraft of air in the clouds and the weight of the raindrops formed.
These storms often produce wind and weak tornados. Multi-cell cluster storms cause flooding, and the cells formed are carried down towards the earth by the wind. These storms produce heavy rain over one large area.
These storms often have more than one cell that forms in a cluster pattern of several clouds. A cell is a mass of air that has up and down air currents. It creates large amounts of rainfall over small areas.
Another type of thunderstorm is a multi-cell squall line that produces winds and hail. Several cells form along a front or boundary, and cool air enforces this boundary. It often stretches hundreds of miles.
This type of storm lasts hours and creates damage from the strong winds and hail. It produces clouds lower in the atmosphere that creates cloudiness. The lower cloud is called the shelf cloud.
Supercell thunderstorms are the most threatening, creating hail, flash floods, tornados, and strong winds. These storms last hours, and winds changing direction in the air mass creates rotating wind within the storm.
They produce most of the tornados in the US and large hailstones. Winds in these storms can reach 100 miles or more.
What is lightning?
In the thunderstorm cloud, ice crystals form and bump into each other, causing an electric charge. Eventually, the entire cloud or air mass fills up with ice crystals at the top of the air mass.
The negatively charged particles sink to the bottom. When the negative and positive charges get big enough, a spark or lightning occurs. This is similar to static electricity sparks that consumers see at home but is much bigger.
Lightning is hotter than the sun and sometimes is caused by negative ions in the clouds that are attracted to positive ions on the ground.
Lightning heats the air around it because it is so hot that thus creating a booming sound called thunder. The air expands fast from the heat and cools quickly, creating the sound known as thunder. Most lightning will occur inside a cloud, But sometimes it occurs outside between the cloud and the ground. It can strike trees, rods, and even people causing severe injury and damage.
There are several different types of lightning produced by storm clouds. Cloud to ground lightning is the most common and occurs in a zig-zag pattern that hits the ground and often returns upward to the air mass or cloud.
This is called the return stroke of the lightning bolt. Intra cloud lightning occurs within the clouds and does not reach the ground. Sheet lightning will light up the cloud producing bright light inside. Heat lightning may be produced when the clouds are too far away to hear thunder.
It often produces a reddish color similar to sunset due to the heat generated. Spider lightning is described as horizontal lightning often seen on the underside of clouds. These are a few different types of lighting produced by atmospheric conditions.
Severe Thunderstorms
Severe thunderstorms are described as storms with hail 1 inch or larger with winds over 50 miles per hour. Thunderstorms occur in the spring and summer in climates with warm weather in the afternoon or evening.
Rainfall from severe thunderstorms causes flash flooding, brings down trees, powerlines, and destroy homes. Lightening from severe storms causes many fires around the world. Large hailstones can damage property and kill livestock on farms. These severe thunderstorms occur in the United States and around the world.
Severe thunderstorm warnings are issued by the NOAA Storm Prediction Center when weather conditions create a serious threat to property and life. Damaging winds are a part of severe thunderstorms.
When the storm comes, residents should unplug appliances and go to a part of the house that does not have many windows. They should talk about safety procedures in thunderstorms with the kids and family and how they will react.
When severe thunderstorm warnings are issued, stop outdoor activities or change the time and date of the event. When walking outside and a storm occurs, stay away from trees, powerlines, fences, towers, and telephone lines.
Try to find a building to go inside if you are walking outdoors in a residential area. When inside the house, turn off the phone, TV, computers, and electrical appliance until it passes. Install lightning rods and keep debris cleared off the property.
Take in lawn furniture and tools that can be blown away. Overall learn to practice safety during a severe thunderstorm.
Tornados and Their Relation to Thunderstorms
Most tornados form from thunderstorm clouds. The clash of warm and cool air creates a destructive column of wind and air rotating in the atmosphere. Some tornados produce winds up to 300 miles per hour capable of destruction.
These storms destroy buildings, uproot trees, and hurl vehicles into the atmosphere. A change in the wind can increase their speed, and the area of rotating air inside the tornado can be 2 to 6 miles in length.
What causes thunderstorm clouds to form tornados? First, tornados form when warm moist air meets cool, dry air. When the cold air pushes past the warm, it creates thunderstorms.
As the warmer air rises, it creates winds that rotate at varying speeds. When it receives more warm air, it increases in speed, and cold air increases the tornado’s energy. Water droplets and moist air form a funnel cloud.
It looks like a funnel, and many tornados have several small tornados within the mass. It is a rotating funnel cloud until it hits the ground.
A Supercell thunderstorm that lasts a long time often produces a tornado that lasts a long time on the ground. A tornado is often preceded by a thunderstorm with hail, thunderstorms, and wind.
Once the rotating funnel cloud hits the ground, it becomes a tornado. These storms can occur at any time of day. The peak time in northern and southern states in the United States is March thru the summer months.
They occur in the Great Plains and Tornado Alley, which encompasses the states of Texas, Kansa, Nebraska, Oklahoma, South Dakota, North Dakota, Missouri, Arkansas, and Louisiana.
A microburst is sinking air inside a thunderstorm less than 3 miles in size. These storms can cause damage due to high winds. A weak tornado that is formed over the ocean, a river, or a lake is called a waterspout. They sometimes move inland, causing tornados and damage property.
The scene of the tornado in “The Wizard of Oz” is considered very realistic. The movie made in 1939 shows the house being lifted in the air and the swirling funnel cloud.
This movie shows how destructive a tornado can be. The special effects used were very simple but created a realistic scene of a tornado and its destructive power.
