Hector the Convector – the most reliable cloud in the world

There’s a thundercloud in Australia that appears at about the same time every day for months on end, and it’s called Hector.

The Hector Convector, described by some as the world’s most persistent thunderstorm, is a convective cloud that forms over the Tiwi Islands in northern Australia. Hector is incredibly punctual and reliable, turning up at around 3pm almost every day during the northern Australian wet season, which runs from roughly October to April.

Hector is a huge storm, sometimes reaching 20 km into the sky. It often has a large anvil-shaped cap due to the top of the cloud being forced to expand as it hits the base of the stratosphere.

Image: Hector Convector, seen from Nightcliff Pier in December 2010. Source: @weather_watcher_australia / Instagram

How is Hector formed?

Thunderclouds form when warm, moist air is forced to rise into higher levels of the atmosphere. Rising air cools as it rises higher, causing water vapor in the air to condense into liquid droplets, forming clouds. The longer the updraft persists, the larger the thundercloud can grow.

Hector is formed when sea breezes flow around the Tiwi Islands from all directions and collide at higher elevations within the islands. These converging sea breezes cause air to rise, creating a column of warm, moist air that forms tall cumulonimbus clouds.

Image: Satellite imagery showing the formation of Hector on Tuesday, October 22, 2024.

Although the Tiwi Islands are not very high, their pyramidal shape helps lift air upward when the sea breeze blows over the islands.

How can you see Hector?

Hector Convector can be seen from Darwin and surrounding areas of the western Top End of North America. Looking north from the mainland, the cloud will appear in the afternoon and usually remain visible until the evening, sometimes causing bright flashes of lightning at dusk.

Passengers on daytime flights departing from Darwin Airport may also be able to see Hector under favorable conditions.

According to the Bureau of Meteorology, the name Hector was given by pilots during the Second World War who used it for navigation during flights near the Top End.