Lightning during a summer storm influenced by Tropical Wave.

Tropical Waves or Eastern Waves, constitute a type of trough, that is, an elongated area of ​​relative low pressure oriented from North to South.

They move from East to West across the Tropics, causing areas of clouds and thunderstorms that are usually seen behind the axis of the Wave.

These are carried by the trade winds, which blow parallel to the Tropics, and can lead to the formation of Tropical Cyclones in the North Atlantic and Northeast Pacific basins.

These phenomena develop from disturbances that drift off the African continent into the Atlantic Ocean


Their movement is largely influenced by the hourly circulation of the great Azores-Bermuda Subtropical Anticyclone, centered in the vicinity of the islands of the same name, which drives them from the coastal areas of North Africa towards the Caribbean and Central America.

Precisely during the month of July, the arrival of these phenomena in our region has been constant, which have failed to develop into a cyclonic system due to the lack of the necessary conditions for it, something normal for this time of year.

However, they usually generate great rainfall activity on land if they are combined with strong heating and if, in addition, they coincide with the presence of an Upper Low, providing great instability and conditions for the development of summer storms.

Approximately 60% of Tropical Cyclones originate from Tropical Waves, while about 85% of the most intense Atlantic Hurricanes (category 3 and above, on the Saffir-Simpson scale) develop from them.

As a curious fact, I tell you that cyclones can, on occasion, degenerate again into a tropical wave.

If one of them moves quickly, it can have winds as intense or stronger than those of a Tropical Storm.

However, it will not be considered as such unless it presents a closed circulation.

An example of this was Hurricane Claudette in 2003, where the original wave reached winds of 72 km/h (before developing circulation).

Tropical Wave Train moving from East to West.