Wave clouds in action
Some days you can look at a satellite picture and not see anything interesting at all, yet some days it can offer something impressive. Today is an example of the latter.
The weather set up at the moment is a classic one for causing wave clouds. If you look at the satellite picture below, you can see exactly what I mean.
There are waves of clouds across the UK, which are caused by stable air becoming disturbed as it moves over hills and mountains. This disturbance of air is known as mountain wave activity.
The easiest way to think about how the motion of the air is affected is to think of a car that travels a little too quickly over a speed hump in the road.
The suspension prior to hitting the speed hump will be relatively stable, but after travelling over the speed hump will bounce up and down for a period of time.
If there is enough moisture present in the atmosphere when the disturbed air moves upwards, the moisture condenses and forms cloud. A few miles later when the disturbed air sinks, the cloud evaporates as it moves downwards and warms.
This upwards and downwards motion of air can continue for some distance beyond hills and mountains – especially when the wind is fairly brisk.
Given that the wind today is blowing from a north westerly direction, the wave clouds are forming to the south east of the hills and mountains of the UK.
Whilst such cloud formations can look very pretty, this sudden upward and downward movement of air can prove hazardous to aircraft.
A plane flying into an area of rapidly sinking air can experience sudden loss of altitude and severe turbulence, so it is very important that expected occurrences of mountain wave activity are highlighted in aviation forecasts.
If you seeing anything interesting on a satellite picture that you would like to be explained, feel free to ask me. The quickest and easiest way to get in touch is via Twitter – @liamdutton
Image courtesy of NASA/GSFC, Rapid Response
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