Interesting weather over the next few days with very strong moisture laden WSW winds interupted by a brief cold snap. 

http://www.raintoday.co.uk/

Note the rain falling over the pennines, on the otherside it is much drier, in a few spots even sunny - this is the charaturistic foehn effect, and indeed a few spots are showing high temps and low dew points associated with it. I regret not making this thread earlier and although we haven't seen any amazingly high temps there will be another opportunity.

For those that don't know what the Foehn effect is, a brief explanation.

Very moist tropical maritime air on typically  WSW, W, WNW or occasionally NW or SW winds is incident on the mountain ranges of the UK particularly the pennines and Grampians. The air is forced to rise over the pennines, as it rises the temperature cools and the vapour in the saturated air is forced to condense into low cloud, fog and relief rainfall as we currently have over the pennines. The rapid drying out of the air by forcing it to rise over the mountains causes latent heat to be released (from the condensation, this is why steam condensing causes burns), because of the heat released as the air rises, the temperature drop with height is slower than one would otherwise expect. Eventually the now dry air starts to descend down the other-side of the mountain, but keep in mind it is already warmer than it should be because of the heat of condensation, this means that by the time the air has increased its temperature due to the height loss, it is now both dry and very warm. 

The consequences of perfect foehn winds can be astounding. They are responsible for seeing 20C in the eastern Highlands in December and February and 18C in January. This is also the reason Aberdeen is capable of being the coldest place in the country on some days (due to its northern location) and the warmest on others (due to it being lee of the hills).