On Thu, 22 Oct 2020 07:09:32 -0700, Tango Whisky wrote:

I had that one over Norther Germany (whis is as flat as flat can be).
Cloud streets with base at 1200 m and tops at 1800 m. Wave lift started
just under the base in front (upwind) of the cloud, and I managed to go
over the tops.
You need a wind shift of 30° or so at cloud base level, with the air
becoming stable (and the convective layer to be significantly unstable
so that the thermals are pushed far into the stable layer above).

I've seen that too, in Cambridgeshire, UK directly over our airfield, but
the bases were lower - only 1200-1400 ft with a fairly brisk breeze,
blowing. The first time I saw it, the streets had short branches almost
at right angles to the street. It was possible to slope soar 150-200 ft
up the front of a branch. The second time there were no branches but
there was lift enough to climb up and over the street and then glide down
on the other side. I don't recall there being sink on the way down and
don't remember whether there was a crosswind under the street, which was
more or less circular in cross section.


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Martin | martin at
Gregorie | gregorie dot org