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The bends in the Jetstream (Roxby Waves) seem to be getting bigger and remaining semi stationary much more often these days. The extreme weather before and after the bends just hangs in there for a long time!
Rob
When I see these type of high clouds I often go to windy.com and set the pressure/altitude slider (on the right side of the screen) to about 200hPa (about 40,000 feet). You can then see the Jetstream winds and these clouds are often just around the points where the Jetstream has twists or turns.
Rob
I am in the Blue Mountains to the west of Sydney. Bunbury would be about as far as New York is from you!
The synoptic chart for the 2nd of Feb is at https://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive_maps.php?arcdate=02/02/2021&selmap=2021020215&maptype=print_us
There doesn’t seem to be any weather data for Wildomar but a flick around the nearby weather stations shows the wind at ground level to be all over the place… https://www.wunderground.com/history
The synoptic chart is certainly conducive to winds that change with altitude which could trigger air mass wave systems. But you are also surrounded heaps of mountains which could trigger mountain wave systems.
The wonderful thing about the weather is that no matter how much left brain might you throw at it sometimes you just have to say “Who knows” and switch over to the right brain and enjoy the photo!
Interesting day!
Rob
It could be a wave system which was triggered downstream of a mountain range but it looks more like an air-mass wave system which develops when different layers in the atmosphere have very different wind speeds and directions….same physics as wind over the ocean.
Were the clouds (which indicate the wave crests) moving or stationary?
If you can give us the location, direction the camera was pointing as well as the time and date, it may be possible to work out from the weather archives what was happening.
Rob
Thank you for kicking off the topic!
Windy.com has a neat feature where you can choose the wind map to display winds at the different altitudes. There is a slider on the right side of the screen.
I have found that many interesting high clouds are associated with a sudden wind change. These shear layers are also responsible for turbulence in aircraft.
The boundary between different atmospheric layers tends to act similarly to the boundary between the ocean and winds above. Waves are created in both circumstances.
Rob
I just checked the weather data and there was a front that went through…
…. and the wind direction reversed around midday.
https://www.wunderground.com/history/daily/KBOI/date/2020-12-8
This type of situation is often associated with very different winds at different altitudes which can trigger air mass wave systems which are not necessarily associated with an underlying mountain range.
Rob
When you get an unstable layer in the mid levels (10-15,000 feet) and a stabler layer lower the convection down low can be weak and cloudless but in spots breaks through to the unstable layer and whoosh, the warmer air goes up, sometimes forming clouds like this.
The line up of the clouds in this photo seems to indicate that there is a wave system and the convection is breaking through along the line of the crest of a wave.
Rob
It looks like there are three layers with the wind in different directions.
The lower layer with alto-cumulus and not much wind.
And the two upper layers with cirrus, fairly windy with the wind direction nearly at right angles.
Rob
I live in Australia (near Sydney) and contrails are not as common as in the Northern Hemisphere. Two reasons….a lot less planes and often dryer upper air which is less conducive to contrails.
When I have been on international holidays I often get surprised by how many contrails there are.
I guess with so many planes grounded now the skies everywhere are clearer of contrails!
RobHaving a windsock in the picture is handy! The upper winds are likely be the same as the windsock and also be flowing left to right.
I would hazard a guess and say that the Alto Cu is forming in the crest of an upper wave system which is orientated directly towards and away from the photographer.
I had a look at the map and think I have my bearings correct….The hill country to the SW of the lake may be the trigger for this wave system. The SW winds would pass over flatter country in Washington State and then be kicked up by the high areas around Mica Peak which is about 2,600′ above the flat country and to the left of the picture.
The storm that Gavin was pondering upon may well be forming under the next crest of the wave system to the right.
Rob
