Originally Posted by Sailor g
That cloud is amazing. I lived in Nevada where air currents over the Sierras made wild cloud patterns. ...
I come from soaring/gliding and those "lennies" get us all excited. They happen when laminar flow of air at higher speeds crosses mountain ranges (lots of conditions have to apply - angle, speed, topography, wind
speeds at different altitudes, thermocline, etc.) but those clouds are signposts of standing lee waves. With few exceptions, altitude records were set using lee waves and long-distance flights often use this phenomena - I got one leg of my 1000km diamond flight in wave conditions off the sierra Nevada.
I got up to 28,000 feet above lennies in Utah around Brian Head
The airflow is laminar (unlike in the lower rotor clouds at mountain level) up there and it feels like you are in still air but the altimeter just keeps on unwinding!
CORRECTION - I just looked at the (wonderful) picture from S/V Jedi, but unfortunately that wisp of cloud is not a lenticular one. It is most likely the beginning of a cumulus cloud, a thermal is lifting moist (a relative term) air at speed to where it becomes saturated and turns into visible vapour.
Here's a picture of stacked lennies over a mountain, usually these are found each wavelength of the standing lee wave, often stacked.