August 26, 2022

The Levanter cloud.

 

Found via "Remarkable ‘Levanter’ cloud seen over the Rock of Gibraltar" (WaPo), which explains that "the Levant wind that blows eastward across the local terrain," and "[m]oist surface air is forced upward by the sudden spike in topography and ascends to a height where the temperature is cooler than the surface air’s dew point" where it "condenses, forming a cloud."

30 comments:

rhhardin said...

Note the top starts laminar and changes to turbulent. The inflection point of the velocity profile across a shear flow is the unstable point. Any disturbance there grows exponentially.

Michael Ryan said...

Something about the description in the WP is not right. The airport is north of the Rock, so this view is to the due south. The wind is blowing from the left (east) towards the right (west), so it's actually a "westward" wind.

Owen said...

Beautifully illustrates the atmospheric physics. Which perform free of charge, everywhere, 24/7. Just take air and heat and add…water.

A similar effect can be seen in mountains with lenticular clouds.

Howard said...

Not as spectacular as the lenticular clouds that form on the downwind side of the Sierra Nevada.

MadisonMan said...

A common event (link). Next, the internet will re-discover Hector.

Owen said...

rhhardin @ 7:46: “…laminar…turbulent…inflection point…shear flow…grows exponentially.”

Yeah. I was just gonna say that.

Leland said...

If that mountain was an airplane, “look at them seeding the clouds to create mind controlling rain”
If that mountain was a cooling tower, “look at all that smog being created that will create acid rain”
Engineer looking at the mountain, “a good view of what happens when you throttle flow in a system”

Original Mike said...

Hector: "Named by pilots during the Second World War, the recurring position of the thunderstorm made it a navigational beacon for pilots and mariners in the region."

The Great Red Spot called. He wants a real name, too.

Drago said...

I place the odds at 50% the democraticals will declare this phenomenon "cloud murder" and blame Trump environmental policies for it.

I can see another FBI raid in our future.

Earnest Prole said...

You see the same thing in San Francisco Bay from time to time.

Howard said...

It's always where it's from, not where it's going. A noreaster doesn't blow in from the south.

Earnest Prole said...

The wind is blowing from the left (east) towards the right (west), so it's actually a "westward" wind.

Exactly — an easterly wind blows westward.

Narr said...

"The Great Red Spot . . . wants a real name, too."

Clifford?

MadisonMan said...
This comment has been removed by the author.
Mary Martha said...

Beautiful.

Also amazing is the car traffic that crosses the runway. I think that's the only place int he world with that kind of traffic concern.

Michelle Dulak Thomson said...

The first thing I thought of was "wave lift!" Yes, lenticular clouds are associated with this; and yes also, the downside to the super-smooth, effortless lift, when you're in a sailplane, is the rotor, an angry gray cloud that conceals forces which (IIRC) once distributed parts of a sailplane over a couple-hundred-mile radius. But the lift itself is spectacular.

Earnest Prole, I lived in the Bay Area for 25 years and never saw anything like this. There's no geological formation that would remotely support it.

Wilbur said...

The Rock of Gibraltar always reminds me of "The 20th Century" a CBS filmed history or documentary TV show hosted by Walter Crankcase that aired on weekends when I was a child. I was fascinated by shows like that.

It was sponsored by Prudential Insurance, hence the Rock Of Gibraltar was featured in the opening and closing. The theme music therefor was memorable.

Anyone else remember it?

mikee said...

I've seen clouds pouring through a mountain pass like a waterfall, a sight to behold.
And add sunlight to clouds and you get some amazing effects.
https://imgur.com/gallery/LUrK1je

Narr said...

I've seen a hundred starships burning at the Tannhauser Gate . . . Actually that was someone else.

Wilbur, I recall "The 20th Century" very well.

Dom, dom-dom, dom-dom, dom-dom, dom-dom-de-dom.

Earnest Prole said...

Earnest Prole, I lived in the Bay Area for 25 years and never saw anything like this. There's no geological formation that would remotely support it.

You have to pay attention. I've seen the same phenomenon on Angel Island and El Cerrito de San Antonio, now known as Albany Hill.

Owen said...

Wilbur @ 12:20: I can still hear Cronkite intoning his narrative of the World At War or whatever the official title was. I was just old enough to want to see the grainy clips of WW2 mayhem. The more mayhem the better, in my opinion as a clueless five-year-old.

And yes, I equated “The Rock” with absolute indomitability. And with Prudential, although in later years I never had occasion to buy their products.

Rusty said...

For Howard;
It's water vapor, Howard.

Baceseras said...

Some names for the winds of the world, listed by Guy Murchie, in I know not what piece of writing, excerpted in The Practical Cogitator (1945 and subsequent editions):



. . the brickfelder of southern Australia; the harmattan of North Africa; the belat, maloya, imbat, chubasco, bora, tramontane, leste, simoon, galerna, chocolatero, bize, crivetz, etesian, baguio, elephanta, sonora, ponente, papagayo, kaus, puelche, siffanto, solona, reshabar, purge, and others. . .

Narr said...

foehn, scirroco, mistral . . .

exhelodrvr1 said...

Climate change!!

Joe Bar said...

Downwind takeoff? Impressive!

Joanne Jacobs said...

I thought of Donald Trump's hair.

Joanne Jacobs said...

I saw Donald Trump's hair.

Aught Severn said...

Discussions of levanter and other Mediterranean wind names always bring to mind the first book of the Aubrey Maturin series for me: Master and Commander.

Randolf said...

The aircraft in the picture is not taking off. At Gib, takeoffs are to the east over open ocean. That plane is taxiing to the west end of the runway to turn around and take off against that rather obvious east wind. The video is speeded up.

Nearly 50 years ago, I would occassionally fly into Gibralter from the U.S. Rota Naval Station in a Piper Cherokee. That rotor on the lee of the ridge that is The Rock once caught me on base leg before turning on final for landing. The plane was almost on it's side before I got it back level. The Royal Navy WREN tower operators would give three winds to incoming aircraft over the Bay of Algeciras: approach on Base leg, wind on Final, and wind on the takeoff end. Memories!