Foehn effect: How Scotland reached close to 20°C

Kinlochewe in Scotland soared to 19.6°C over the weekend, but how did temperatures climb so high?

Well, there are a few things to consider. On a larger global scale, the warming climate. On a national scale, the mild southerly air drawn up from Africa, and, on a local scale, the foehn effect.

So how does the foehn effect enhance the mild air we're already encountering, particularly when just a short distance away temperatures were quite a bit lower?

This temperature difference is because of something called the foehn effect which changes wet, cool air on one side of a mountain to warmer, drier air on the other.

As air moves over a mountain, it cools. This causes water vapour to condense into clouds and give rain on the windward side of the mountain.

Once the air crosses the mountain it begins to descend again as drier air. Dry air can warm quicker than moist air, so on the lee side of the mountain things are often sunnier and warmer - in this case the north side of the mountains in a southerly air flow.

The foehn effect can happen anywhere in the world, as long as there is a wind and some mountains where the larger the mountains, the larger the warming affect can be.