September 20, 2011

Breeze Fronts

This week we had some local fires that were started by dry lightning. Overall a bad thing but it did provide an opportunity to capture the daily afternoon phenomena of the breeze front (AKA Sea Breeze Front) pushing through the Tehachapi, CA valley on it's way to spilling into the desert floor near Mojave, CA.

The breeze front is the cool stable air from the San Joaquin Valley pushing east as the thermals in the desert start to die and no longer act as a thermal block to the normal west to east trade winds.

The breeze front, though itself stable, promotes thermal development by providing relatively cool air to help the last little bit of heated air in the super adiabatic layer to separate from the ground and form thermals. Thermals form at the boundary of the cool stable air and warm unstable air.

So here is a picture of what I am talking about. You can see the cool stable air moving in the from the right, marked by the smoke it carries with it, and the clear unstable air on the left. The Raged cu in the upper right are normal indicators of the thermals produced by breeze fronts.

See Reichmann, "Cross Country Soaring" Pages 27-29 for more information.

I hope you now better understand a common soaring weather phenomena.

Keep soaring,

1 comment:

  1. Hey Michael - after soaring in Tehachapi for more than 25 years I learned something completely new. Thanks for posting this. - Bill Brewer