Understanding Thunderstorms: Formation and Characteristics

Storms are atmospheric disturbances, while thunderstorms are storms specifically with thunder and lightning.
Thunderstorms can occur almost anywhere, with severe thunderstorms potentially leading to tornadoes and hurricanes.
Most thunderstorms move with the wind flow in the troposphere.
Approximately 16 million thunderstorms occur worldwide annually.
The US experiences about 100,000 thunderstorms each year, with 10% reaching severe levels.

Thunderstorms develop in cumulonimbus clouds, which are tall and dark.
Thunderstorms are often accompanied by strong winds and precipitation, however sometimes there can be no precipitation.
Updrafts, caused by warm, moist air rising and mixing with the atmosphere, lead to thunderstorms.
Thunderstorms commonly form at the collision points of warm (tropical) and cool (polar) air masses.

Moisture, unstable rising air, and a lifting force (heat) are essential for thunderstorm formation.
Solar heating warms the Earth's surface, which in turn heats the air above, causing it to rise through convection.
Convection transfers heat from the Earth's surface to higher atmospheric levels.
As rising air cools, water vapor condenses, forming cumulus clouds because cool air cannot hold as much moisture as warm air.
Convection cells, which are unstable air, are created by the cycling of rising and falling air.
Thunderstorm clouds can reach over 33,000 feet in altitude, with some exceeding 66,000 feet.
Cumulonimbus clouds turn dark as they grow taller.
Electricity builds within the cloud as ice particles collide, leading to lightning and thunder.

Storms originate from rapid upward movement of warm, moist air.
The force needed to push air upwards can be a front, shortwave trough, or another system in the air.
A trough is a long low pressure system that pushes air upwards.
As warm air rises, it cools and condenses into cumulonimbus clouds reaching over 12 miles high.
Downdrafts are cooler air sinking back to the ground because falling water droplets drag cooler air down with them.
Storm cells are created by the combination of warm updrafts and cool downdrafts.
The process repeats until the air temperature stabilizes and an anvil-shaped cloud (anvil head) forms.

Thunderstorms progress through three stages: developing, mature, and dissipating.
Developing Stage: Characterized by a cumulus cloud pushed upward by an updraft, with increasing height and little to no precipitation
Mature Stage: Updraft continues, precipitation begins, creating a downdraft, and wind speed increases with heavy rain, hail, lightning, and potential tornadoes
Dissipating Stage: Downdraft overcomes the updraft as precipitation decreases, and the storm breaks up due to a front cutting off the warm, moist air supply

Single Cell: Small, weak, and short-lived storms (typically an hour) driven by daytime heat; also known as "popcorn" storms.
Multi-Cell Clusters: Multiple storm cells spread out, forming from new updrafts along the edge of rain-cooled air (the gust front); can produce hail, strong winds, brief tornadoes, and flooding.
Multi-Cell Lines: Also called a squall line, it is a line of storms with high winds and heavy rain.
Supercells: Long-lasting, organized storms powered by a rotating, tilted updraft, often leading to large and violent tornadoes
Severe Thunderstorms: Defined by hail one inch or greater, winds exceeding 58 mph, or the presence of a tornado; can arise from any type of storm cell.
Mesoscale Convection: A system of thunderstorms acting together, potentially spanning an entire state and lasting over 12 hours, featuring a low-pressure center and vortex that can initiate new thunderstorms or, over warm water, a tropical storm or hurricane.

Spring and summer are the most common seasons for thunderstorms, though they can occur year-round.
Lightning: Electrical discharge caused by colliding ice particles, creating electrical charges that release energy, heating the air, and producing thunder.
Hail: Chunks of ice precipitation formed within an updraft, posing risks to property, animals, and people.
Tornadoes: Rapidly rotating vortices extending to the ground, rated by wind speed, causing significant destruction quickly.
Flash Floods: Result from intense rainfall overwhelming the ground's absorption capacity, leading to fast-moving water that can damage property and infrastructure.
Downburst: Strong winds from high-pressure systems sinking, causing damage to buildings, crops, and trees.
Storm Asthma: Asthma attacks triggered by thunderstorms, where pollen absorbs moisture and bursts into numerous particles, increasing pollen count in the air.