in General, Tropics

African Easterly Wave

It is still early in the tropical season, but it has been relatively active thus far in the Atlantic Basin. Firsthand Weather is monitoring a robust African easterly wave over sub-Saharan Africa that will move into the eastern Atlantic later this week (around June 28th).

Water Vapor Imagery Of Wave

While not impossible to see development, it is still early in the season to look east towards Africa. (This region heats up from late July through September as African easterly waves have a more favorable shot at development due to atmospheric parameters.) As the current wave we are monitoring moves into the Atlantic, it is possible it will undergo an increase in convection, but the chances for tropical cyclone development are low. Environmental shear values are moderate and the system will encounter dry air, but we will continue to monitor the evolution.

GFS Surface Pressure & 10m Wind Map (Thursday Night)

European 850hPa Wind & MSLP Centers Map (Friday Morning

This wave we are monitoring serves as a good segue to dive into African easterly waves.

What are African easterly waves? Why are they important?
African easterly waves are areas of energy with an associated spin that form due to airmass contrasts (temperature and moisture) across northern Africa. Using a pyramid as an analogy, the wave acts as the bottom piece of the pyramid and can serve as the foundation for tropical cyclone development. This tropical cyclone development can occur as the wave moves off of the coast of Africa, if the wave maintains its strength, and atmospheric conditions (low shear and moist conditions) and SST are favorable (warm). These tropical cyclones can then move east-northeast and impact the Caribbean Islands and the continental United States.

Firsthand Weather will keep a close eye on the tropics over the coming months!