How Harmattan winds will sprinkle a covering of Saharan dust across the UK this weekend

If you are considering washing your car this weekend - it is probably best to wait.

Saharan dust is likely to settle on cars across the UK on Sunday and Monday, potentially affecting air quality too.

Saharan dust is visible on satellite imagery across west Africa and the Canary Islands.

For anyone who holidays there at this time of year, the phenomenon of Saharan dust will be something familiar, making the sunshine very brown as the dust is suspended high in the atmosphere.

So how can something that is 4000km away reach the UK in just a few days?

The Harmattan

The Harmattan is a season in West Africa, and it runs from November to the middle of March.

The biggest feature of this season is dry and dusty northeasterly winds.

Cold nights, poor visibility and poor air quality are other common features and it is not usual to have powerful sand and dust storms.

The dust can drift offshore affecting nearby islands to as far as northern Europe.

How can the dust travel to the UK

A key factor in Saharan dust being transported to the UK is time - you need sustained upper wind for a period of days.

This provides uninterrupted travel for the dust in one direction, long enough for the flow of air to reach the UK.

When it reaches the UK, it normally gets washed out with rain or loses momentum with changing wind direction and ultimately starts to visible settle, most noticeably on car bonnets.

As you can see from the map below, the dust is likely to affect air quality.

The air quality forecast is expected to lower by Monday, affecting parts of Wales, central and southern England.

You can find out more about Air Quality across the UK here.

If you would like to learn more about climate change click here.

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