I've posted before about the model of the Aber valley that we found when we went to the Aber Falls. Abergwyngregin at the foot of the valley has been in the news because of some very high temperatures recorded at this time of year. It was the subject of the weather column in The Times newspaper yesterday. The reason for such high temperatures on the north coast of Wales is given as the Foehn Effect
https://www.youtube.com/watch?v=pJqQoUXMquQ https://en.wikipedia.org/wiki/Foehn_wind There are several parts to the warming effect but the first part is that as air rises, the pressure is lower so the temperature falls and this means that water vapour condenses. The change of state releases latent heat - the heat energy is the reason why the top of cumulus clouds are lumpy when the bottoms are flat. This latent heat warms the air. The process is irreversible because the water leaves the air as rain. In the case of Abergwyngregin, the rain falls over Snowdonia and the warmer, drier air sweeps down the valley. Drier air means more sunshine so making it warmer still. The film and article cited give the other components to the warming. I now need to figure out why Wigton doesn't seem to benefit from the Lake District mountains in the same way.
