Orographic lifting based on whatever winds prevail.

Waves exist downwind from the obstacle that created them.

Mountain Wave
 

I fly in northern Scotland and often plan my routes to avoid the local mountain wave we experience. Thinking back over my last 10 trips, i've experienced some mountain wave effect on at least half of them. Any reasonable (say >20KTS at or below 2000) westerly or south westerly and its a 99.9% certainty you will be sinking if you head off in the wrong direction (high terrain is around 10NM's away). On this basis, its hard to avoid it being taught when you learn to fly here! We do get some very nice lenticular clouds, particularly in April & May!

The technical term for them on the slopes in Scotland is tube or muppet or feel bawbag if they have been really stupid. I have never heard a snow boarder being acused of being intelligent.

are these anabatic winds then?
such as

Anabatic Kiteboarding. NZ's Auckland based kitesurfing importer and retailer. Into Wake boarding? Snowboarding? Surfing or Skateboarding? Then you will love kiteboarding. - Lessons Information

Listen very carefully. I will say this only once. (Spoken in a faux french accent, as in 'Allo Allo'.)

Orographic.

Forced upward movement of air upon encountering a physiographic upland. This lifting can be caused by two mechanisms:
1) The upward deflection of large scale horizontal flow by the Orography.
2) The anabatic or upward vertical propagation of moist air up an orographic slope caused by daytime heating of the mountain barrier surface.

gotcha,

Merci ;)

The picture perfect storm: Photographs capture the terrifying beauty of clouds gathering over Greenland | Mail Online

This is really exteme.

Mt. Rainier puts on a show! | KOMO News - Seattle, Washington | Weather Blog

good examples (as well as nice pics!) where you see what the way the air flows over a mountain

I was going to go flying today but was put off by the following scene (and NO I don't mean the runway was under water! :rolleyes:) ....

http://i145.photobucket.com/albums/r...ntainWave4.jpg

http://i145.photobucket.com/albums/r...untainWave.jpg

There are 2,500ft mountains to the east of us and a 25 mph easterly wind was blowing. The lenticulars were forming at just over 2,500ft, I didn't go and have a closer look. It looked like wave was carrying on over the Pacific for quite a number of tens of miles.

There have been satellite photos of wave bars all the way from Scotland across the North Sea to Norway - which led to suggestions that a Scotland - Scandinavia glider flight might be feasible. :ooh:

I never heard of anyone trying it though! :uhoh:

Hi Skyhawk

You don't worry when the sky looks like that.

But when it looks like this, be careful

http://i38.tinypic.com/317cz6u.jpg

I don't think we have mountains near us big enough to cause that spectacle, the Cascades some 80 miles to the east could and I would really like to see that happen. When there is just a light easterly along the coast here the fillings bounce out of your teeth. I know that flying when lenticulars are visible will not be dangerous, just very unpleasent for an afternoon bimble.