Hi,

This morning on my way to work in NYC I saw lenticular clouds over
some low level clouds. Is that what I saw?

It was a bit breazy this morning (Sep 25) and the clouds were broken
and low, perhaps hundreds of feet above the ground. Planes flying out
of LaGuardia Airport were in and out of the clouds less than a minute
after take off.

The lenticular clouds looked just like pictures I've seen of them over
mountains. I didn't know they could form over other clouds.

Any explanations would be appreciated.

Thanks,
Andy

AMH wrote:
Hi,

This morning on my way to work in NYC I saw lenticular clouds over
some low level clouds. Is that what I saw?

It was a bit breazy this morning (Sep 25) and the clouds were broken
and low, perhaps hundreds of feet above the ground. Planes flying out
of LaGuardia Airport were in and out of the clouds less than a minute
after take off.

The lenticular clouds looked just like pictures I've seen of them over
mountains. I didn't know they could form over other clouds.

Any explanations would be appreciated.

Thanks,
Andy

Lenticular clouds are not limited to *mountain* areas. It does not take
much of a perturbation to set up the wave action if the conditions are
correct with respect to stability in the layer. Any small bump on the
landscape, and well upwind from the cloud location, can trigger the
waves. The low clouds were probably formed by some totally separate
process and had nothing to do with the lenticulars, which in turn
probably had nothing to do with the low clouds...



--
God grant me the serenity to accept the things I cannot change, the
courage to change the things I can, and the wisdom to know the difference.
--- Serenity Prayer

Icebound wrote:
AMH wrote:

Hi,

This morning on my way to work in NYC I saw lenticular clouds over
some low level clouds. Is that what I saw?

It was a bit breazy this morning (Sep 25) and the clouds were broken
and low, perhaps hundreds of feet above the ground. Planes flying out
of LaGuardia Airport were in and out of the clouds less than a minute
after take off.

The lenticular clouds looked just like pictures I've seen of them over
mountains. I didn't know they could form over other clouds.

Any explanations would be appreciated.

Thanks,
Andy

Lenticular clouds are often "medium-level" clouds (i.e. approx
10,000ft).They are sometimes accompanied by "low-level" clouds
close to the lee side of the mountain. These clouds are called
"roll-clouds" and can indicate turbulence. The roll-clouds may
not be particularly tall, being limited by air descending from
the lenticular cloud layer above.

Icebound

Lenticular clouds are not limited to *mountain* areas. It does not take
much of a perturbation to set up the wave action if the conditions are
correct with respect to stability in the layer. Any small bump on the
landscape, and well upwind from the cloud location, can trigger the
waves.

Not all lenticular clouds result from waves. Some lennies are the simply the
result of high speed wind.
---
- T Q -

Start every day off with a smile...and get it over with.
-- W.C. Fields --

TQ wrote:


Not all lenticular clouds result from waves. Some lennies are the simply the
result of high speed wind.
---


Well, typically to get a cloud, you need condensation, which requires
cooling, which typically requires a pressure reduction, which is usually
accomplished by lifting at the entrance side and descent on the exit
side. That's sort of a wave.... again: typically.

You may be right, but I am not exactly sure how you may get lift from
strong level wind, unless it is perturbed somehow.

--
God grant me the serenity to accept the things I cannot change, the
courage to change the things I can, and the wisdom to know the difference.
--- Serenity Prayer

C wrote:
Icebound wrote:

Lenticular clouds are often "medium-level" clouds (i.e. approx
10,000ft).They are sometimes accompanied by "low-level" clouds
close to the lee side of the mountain. These clouds are called
"roll-clouds" and can indicate turbulence. The roll-clouds may
not be particularly tall, being limited by air descending from
the lenticular cloud layer above.


Absolutely true...

But they can and do also occur in non mountain areas such as Southern
Ontario. I've seen them. It just takes a very stable airmass, strong
windflow at mid levels, and a perturbation to get a wave action so that
there is some lifting and condensation at the entrance and downflow and
drying at the exit.

The roll clouds are normally at cumulus level... What the poster
described seemed to more likely stratus fractus in the morning, probably
having nothing to do with the cloud above.

--
God grant me the serenity to accept the things I cannot change, the
courage to change the things I can, and the wisdom to know the difference.
--- Serenity Prayer