Thunder Rain or Thunderstorms are weather phenomena that occur due to disturbances in the atmosphere, and are characterized by the presence of lightning and thunder. However, they are not limited to those features—thunderstorms may also bring varying intensities of rainfall, hail, and strong downdraft winds that originate from cumulonimbus clouds. These storms may develop from a single cumulonimbus cloud or a line of connected thunderstorm cells, which can sometimes stretch for hundreds of kilometers—especially in severe cases or deep low-pressure systems.

Formation

Thunderstorms form when warm, moist air rises in a relatively stable atmospheric environment. For upward lifting of air to begin, several key factors must be present, including:

Uneven heating of the Earth’s surface
The effect of terrain, which creates zones of wind convergence where surface winds meet—this is especially common in elevated areas like the Hajar Mountains during summer
Lifting of warm air along frontal boundaries, which often triggers severe thunderstorms and tornadoes

Scattered thunderstorms are usually ordinary storms that occur away from weather fronts, tend to be short-lived, and rarely produce damaging winds or large hail.

Stages of Thunderstorm Development

Thunderstorm clouds go through three main stages:

1. Cumulus Stage (Formation)

Warm, moist air starts to rise, cools, and condenses to form cumuliform clouds—if the atmospheric conditions are favorable. During this stage, clouds may evaporate or dissipate due to mixing with relatively dry surrounding air, but this can increase moisture content at that level and lead to more condensation at higher altitudes.

2. Mature Stage

This stage is marked by the presence of both updrafts and downdrafts. The cumulonimbus cloud grows so large that updrafts can no longer support the weight of water droplets inside it. Thunderstorms, rain, and lightning occur during this phase. Whether the rain reaches the ground depends on humidity levels in the lower atmosphere below the cloud.

3. Dissipating Stage

Downdrafts dominate, while updrafts weaken. This cuts off the cloud’s supply of warm, moist air. Light rain may continue as the cloud gradually dissipates. In some cases, downdrafts can force more warm, moist air upward again—potentially forming new thunderstorm cells.

Severe Thunderstorms

These are storms that produce damaging surface winds reaching up to 100 knots (about 185 km/h). They can also cause flash floods, heavy hail, and potentially tornadoes.

Such storms form in regions with strong vertical wind shear (rapid changes in wind speed or direction with altitude). High-altitude winds tilt the updrafts, especially during the storm’s mature stage, separating the rising and sinking air currents. This prolongs the storm’s lifespan and increases its intensity.

As the updrafts become more powerful and vertical wind shear becomes more intense, the storm can start to rotate counterclockwise (in the Northern Hemisphere), creating favorable conditions for tornado formation.

Supercell Thunderstorms

A supercell is a large, highly organized type of thunderstorm cloud—and one of the most dangerous types of severe weather. It produces extremely strong winds, with updrafts exceeding 90 knots (about 165 km/h), and hurls massive hailstones. Supercells are usually destructive.

What distinguishes a supercell from other storm types (like single-cell or multi-cell storms) is its deep, persistent rotating updraft, known as a mesocyclone. This feature allows the supercell to last for several hours and move as a unified, organized system.

These clouds most commonly form in the central United States and are responsible for the strongest recorded tornadoes there.

Types of Supercell Clouds

Classic Supercell
1. The most common type, especially in the Great Plains of the United States.
1. Characterized by large, flat cloud bases and intense updrafts.
1. Produces heavy rain, large hail, and has a high potential for long-lived tornadoes.
High-Precipitation (HP) Supercell
1. Occurs in moist environments with weak mid-level winds.
1. Produces heavy rainfall, often obscuring the storm structure—including the wall cloud and any tornadoes.
Low-Precipitation (LP) Supercell
1. Features minimal rainfall, yet still capable of producing large hail.
1. Usually forms in low-humidity environments, and is often observed in Oklahoma and Texas.
Mini-Supercell
1. A smaller version of the classic supercell, forming mainly in cooler seasons.
1. Characterized by its small size and moderate buoyancy.
1. Typically, doesn’t exceed a horizontal depth of 20,000 feet above ground level.

Note

It is often difficult to distinguish between supercell types, as they can evolve from one form to another during their lifecycle. Regardless of type, however, all supercells form through the same basic mechanisms, no matter their location.

During a severe thunderstorm, your safety depends on staying alert and taking precautions. Here’s what you should do:

Stay indoors and avoid going outside unless it’s absolutely necessary. The safest place is inside a sturdy building.
Avoid using electrical appliances and unplug devices to protect them from power surges caused by lightning.
Stay away from windows, doors, and porches, as strong winds and lightning can break glass or cause other damage.
Do not take shelter under trees or tall structures, which are more likely to be struck by lightning.
Avoid water sources, including bathtubs, sinks, and plumbing, as lightning can travel through pipes.
Secure outdoor objects that could be picked up by strong winds and become dangerous projectiles.
If you’re caught outside, stay away from open areas, isolated trees, and metal objects like fences or poles. Crouch low to the ground, but don’t lie flat.
Monitor local news, weather apps, or radio for updates and emergency instructions.
Have an emergency kit ready with essentials like water, food, flashlight, batteries, and first-aid supplies.

Taking these steps can significantly reduce your risk during a severe thunderstorm.