Would these stratus clouds be bumpy?

[TangoWhiskey]

Just wondering if flying near the bottoms of these stratus clouds, or in them, would be bumpy? It would sure seem like they would be, visually. I purposely altered the coloring and contrast to help accentuate the clouds and what I was seeing, which otherwise don't render well on my cell phone. This was over DFW airport at about 2:00P CT today.

 

[wsuffa]

Yes.

And are you sure they're stratus? Looks like some of the mammus you can get from cumulo-type clouds.

 

[bobmrg]

I agree with Bill S....those aren't plain-vanilla stratus clouds; I'm sure that Scott D will be along to straighten us out. Having said that, I wouldn't hesitate for a moment to climb through them.

Bob Gardner

 

[TangoWhiskey]

They weren't mammus; I know what those are; these looked like high stratus being influenced by a mountain wave upstream. It was hill-valley-hill-valley-hill-valley evenly spaced.

 

[RotorAndWing]

 

[AWACSEng]

Wow, those are nice...clouds.

 

[Snaggletooth]

Wow, those are nice...clouds.

What clouds?

 

[AWACSEng]

What clouds?

You know, the puffy white objects in the picture.

 

[timwinters]

Looks like mammus to me.

 

[TangoWhiskey]

Are the wave crests in this picture oriented northwest to southeast?

Yes, Scott, they were. How'd you figure that out?

The wave-like structure you are seeing isn't related to mountain wave activity.

Yeah, I figured they'd almost have to be north/south crests for that to be the case...

Winds at the surface were northwest, shifting to the northeast at 3,000 feet, east at 8,000 feet (just below the bases) and then shift to the southwest at 12,000 feet (above the deck pictured).

This stratocumulus deck isn't that thick and was capped by an inversion. Don't know what's causing this wave-like structure to occur without spending a couple of hours looking into it.

BTW - It is not likely to be bumpy below the clouds or in these clouds.

KDFW 241853Z 33008KT 10SM BKN080 BKN150 OVC300 23/11 A3018 RMK AO2

Interesting, Scott, thanks. I guess "what it looks like" isn't always "what it is". I didn't think to look PIREPS for turbulence, wish I had.

 

[gismo]

Here's a free workshop that discusses pilot reports...near the end of this workshop, I provide a good memory aid on how you should distinguish between, light, moderate, severe and extreme turbulence.

I wish there was a more aircraft independent and consistent way to describe the intensity of turbulence in a PIREP. As you know moderate turbulence in a C-152 might hardly be felt by a C-421 and pilots tend to over estimate the severity more often than not.

 

[kthompson2k]

I was on the lake yesterday doing a litle fishing and watched those clouds form above Lake Texoma, was pretty cool.

 

[Greg Bockelman]

I have climbed through clouds that looked similar to that in the 777, thinking we would get bounced, and felt hardly a ripple. I was sure we would get bounced pretty good.

 

[TMetzinger]

The thing that led me to believe there wouldn't be turbulence was that they appeared to be a fairly shallow layer of clouds - no thickness=little lift=little mixing=little turbulence.

Now, there might be a hellacious wind shear lurking somewhere above, but the clouds themselves looked benign.

 

[dmccormack]

According to my colleagues developing the Graphical Turbulence Guidance (GTG) product, there's a severe lack (no pun intended) of negative turbulence reports. When the conditions are good, pilots don't report it. Pilots are also under-reporting the severe encounters as well - not making enough reports when they encounter severe turbulence.

Whenever I call Flight Watch with a PIREP, they seem happy and surprised, especially when I report "Smooth ride."

 

[RotorAndWing]

75% of all CAT occurs in clear air, but 25% does occur in stratified clouds or cirrus clouds.

If it occurs in clouds, it's not clear air turbulence.

 

[Bob Noel]

75% of all CAT occurs in clear air.

ummmm. huh?

 

[TangoWhiskey]

Troy,

I got a chance to look at this a bit more. I think the cloud feature you observed could best be classified as a type of "Altocumulus Undulatus". They are formed as a layer of moisture interacts with rising motion and the vertical wind shear I mentioned in an earlier post.

The wind shear I discussed was likely responsible for the arrangement of the clouds into the bands. When you get instability in a layer with vertical wind shear, you'll often get small-scale vertical eddies that create clouds if the relative humidity is high in the layer. The eddies become aligned by the wind shear (often parallel with the wind shear) which in time may result in well-defined bands of cloud like those in your image. In this case, there wasn't a lot of instability below the clouds and the winds were relatively light, so the turbulence was minimal (if any).

This page has a pretty good explanation, but the example picture looks a bit different than the one you posted.

There was some rain falling from these clouds, but the sub-cloud layer was extremly dry (as you can see below from the RUC analysis) and most of the raindrops evaporated before reaching the ground creating virga (harmless) especially throughout the morning. It wasn't until the air saturated a bit more later in the afternoon that a few sprinkles developed around the metroplex between 4 and 5 pm.

You can see from this analysis at 1900 UTC, the winds at the bases of the clouds (8,500 feet) are from the east-southeast (about the orientation of the crests) and they shift around to a southerly flow just above the tops at 9,500 feet.

Hope this makes sense and helps explain the clouds.

You nailed it! Thanks for the information, Scott. It was not humid at all yesterday (or today)--very nice fall weather, and you're right--I got just a FEW sprinkles on the way home (big drops, but just a few). They surprised me, as it didn't appear the clouds were thick enough to produce rain.

 

[TangoWhiskey]

Scott, based on that RUC sounding, could I have expected another layer of clouds about a thousand feet thick at 17K?