Differences Between "Cyclone," "Typhoon," and "Tropical Storm"

When monitoring information about major storms around the world, we often encounter these terms. So, what are their differences?

The GFS Model in the United States is the Global Forecast System (GFS), operated by the National Weather Service, which predicts the paths of storms. It utilizes a supercomputer to run data through a complex algorithm sourced from satellites, observatories, and weather balloons.

Satellite image of Hurricane Michael 2018 in the USA.

Storm Track refers to the progression of a storm’s position and intensity over its duration. The best tracking methods include latitude, longitude, maximum surface wind speed of the storm system, and minimum sea-level pressure over a six-hour period, based on post-storm assessments of all available data.

The European Model is regarded by meteorologists as the most accurate model for predicting storms in mid-latitudes. The European Centre for Medium-Range Weather Forecasts (ECMWF) develops this model, integrating real-time meteorological data into their algorithms (thus starting with more accurate initial conditions) and investing in advanced computing hardware. Both European and American models are predictive mathematical models, so they do not necessarily reflect the storm paths issued by the National Hurricane Center.

The Eyewall is the ring or cluster of cumulonimbus clouds surrounding the eye of the storm. The storm’s extremity is represented in the eyewall: lightning, heavy rain, and high winds.

The Fujiwhara Effect occurs when two tropical cyclones rotate around each other.

A storm is a tropical cyclone with maximum sustained winds of 74 miles per hour (119 km/h).

Storm types are a conventional naming system. Storms are classified into five categories based on their sustained wind intensity, known as the Saffir-Simpson Hurricane Scale.

Category 1: Winds from 74-95 miles per hour (119-152 km/h); very dangerous winds will cause some damage.
Category 2: Winds of 96-110 miles per hour (154-177 km/h); extremely dangerous winds will cause significant damage.
Category 3: Winds of 111-129 miles per hour (178-207 km/h); severe damage will occur.
Category 4: Winds of 130-156 miles per hour (209-251 km/h); catastrophic damage will occur.
Category 5: Winds exceeding 156 miles per hour (251 km/h); catastrophic damage will occur, and most areas will become uninhabitable.

Satellite image of a storm.

Storm Warning is an announcement that storm conditions (sustained winds of 74 mph or more) are expected to occur somewhere within the specified area related to a tropical storm.

Storm Watch is an announcement that storm conditions (sustained winds of 74 mph or more) could occur in a specific area related to a tropical storm.

Latent Heat is the heat required to convert a solid into a liquid or vapor without changing its temperature. When water vapor condenses to form clouds, latent heat (energy) is released, which helps intensify storms by warming the surrounding air and causing disturbances.

If a storm reaches Category 3 or higher, it is considered a major storm.

Maximum Sustained Winds are the standard measure of the intensity of a tropical cyclone. It refers to the highest average wind speed over one minute (at a height of 10 meters with unobstructed exposure) related to that weather system at a specific time.

The Monsoon is not a storm but a large-scale seasonal wind shift over a region accompanied by significant seasonal changes in rainfall.

The Radius of Maximum Winds is the distance from the center of a tropical cyclone to the location of maximum wind speed of the cyclone. In strong storms, the radius of maximum winds is often located on the inner edge of the eyewall.

Storm Surge refers to the increase in sea level following a storm or major cyclone, when the observed sea level is different from the normal level without a storm. Storm surge is estimated by taking the measured sea level after the storm and subtracting the normal tidal level.

Tropical Cyclone is a general term for storm systems occurring over warm tropical waters, such as tropical storms, Atlantic hurricanes, Caribbean storms, and storms in the central and northeast Pacific; as well as typhoons in the northwest Pacific. Tropical cyclones have a well-defined center, and the wind direction rotates counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

A Tropical Depression is a tropical storm with maximum sustained winds below 39 miles per hour (62 km/h).

A Tropical Storm is a tropical cyclone with maximum sustained winds between 39 and 73 miles per hour (62-117 km/h).

Typhoon is a tropical cyclone formed in the Pacific Ocean, located between 180-100 degrees East, with winds exceeding 119 km/h. Typhoons are weather phenomena similar to hurricanes, differing only in their formation location.

Hurricane is the term used to describe Atlantic hurricanes, Caribbean storms, and storms in the central and northeast Pacific. In the northwest Pacific, storms of equivalent strength are called typhoons.

Meanwhile, the South Pacific and Indian Ocean use the general term Tropical Cyclone, regardless of wind speed and weather conditions.

Storms initially form as tropical depressions, and as they strengthen to have maximum sustained winds of around 63 km/h, they become tropical cyclones. Tropical cyclones in the Northern Hemisphere rotate counterclockwise, while cyclones in the Southern Hemisphere rotate clockwise.

If maximum winds reach 119 km/h, it will be classified as a typhoon or hurricane.

Naming Tropical Storms (Internationally)

Tropical storms often last a long time and are named to facilitate quick identification.

The first storm of the year will have a name starting with the letter A, for example, Storm Alice. The next storm will have a name starting with the letter B.

Scientists hold meetings to decide on the list of new names for the following year’s storms.

Names of storms that cause significant damage will never be used again.