Hi guys,

Just had to snap this photo while flying with a student, wasn't quite sure what to make of it? Looks like some mega 180 degree windshear or something!?

Taken on one of the nicest days I've seen in Perth for months, but never mind, there were waves of cold fronts coming through after that!

Ellzy

I remember seeing that effect often when I had my flying school in Ingham in North Queensland. Always in the early morning. I'm not familiar with the topography you were over, but in the case of Ingham we often had a low-level katabatic wind coming down the valley from the west, with a prevailing South Easterly gradient wind above.

The cold air in the katabatic wind was usually only about 400/500 feet deep and above that the prevailing South Easterly took over. Smoke from the sugar mill stack would head off to the east for the first 500 ft and then suddenly swing to the north west when it encountered the South Easterly above.

The effect caused lots of dramas with students doing circuits. The wind sock was indicating a wind in one direction, but the drift on the downwind leg was from the opposite direction. Isn't it great how an instructor can watch a student suffer!!

I doubt if that is the explanation for your photo though, it looks like the low level wind is coming from the sea. I take it that your your photo was taken in the late afternoon since the sun sets over the sea in your country. Maybe the remnants of a sea breeze with an easterly above?

Bob

Yeah Bob that would get a student confused indeed, as if it weren't hard enough already!

It would have been taken about 1730WST, I vaguely remembering landing at Jandakot on 06 so it could possibly have been the easterly taking the smoke out that way.

Wouldn't have liked to be doing a PFL lesson - "OK so what was one of the ways we can figure out wind direction?"