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The Skew-T and extreme turbulence

scottd

Member
If you are not a Skew-T fanatic, you should be. Here's an excellent example of what the Skew-T can do for you. Take a look at this Skew-T analysis from 15Z in southeastern NC.

Extreme-Turb-PIREP-Skew-T-Annot.png


Notice at about 6,500 ft MSL, the winds are from the southeast at 58 knots and then around 9,300 feet, they are from the southwest at 57 knots. This is an excellent example of directional shear in the wind aloft. The key though is the moist unstable layer that starts just below 8,000 feet that enables the air to mix. All of this coupled together is the reason this pilot reported extreme turbulence at 8,000 feet MSL.

UAA-Extreme-Turb.png


If you are not a Skew-T fanatic, make a New Year's resolution to become one!
 
Probably connected with this, yesterday.....

IMG_1422-M.jpg


This was at FL400, around 1400 local. Position is between Richmond and Norfolk heading towards Charleston en route Cancun.

Guys were bitching about turbulence, some were down at FL260 to get out of it.

Meteorology and Climatology are fascinating, both for local flying and us up at the top of the levels.

If you see these -

https://www.youtube.com/watch?v=KureeNtxpr0

Beware - therein lurks dragons and monsters..:D
 
They look very interesting but I have never found a good reference on how to read them. Everything seems to assume a high base level of knowledge already.

For example, what are the features in that chart that indicate moist instability?
What do the other kinks in the line indicate?
 
They look very interesting but I have never found a good reference on how to read them. Everything seems to assume a high base level of knowledge already.

I was thinking the same; to steal a line from Blazing Saddles, that looks like authentic frontier gibberish to me!
 
Extreme turbulence

I always wonder about the ?extreme turbulence? pireps.

By definition, this means that ?the aircraft is practically impossible to control and may cause structural damage?.

Granted this is a subjective thing but I?m curious if this pilot wrote the airplane up for potential structural damage...

The problem is most folks have never experienced that kind of turbulence, so there really isn?t a common frame of reference to decide what is moderate, severe, or extreme....
 
I always wonder about the ?extreme turbulence? pireps.

By definition, this means that ?the aircraft is practically impossible to control and may cause structural damage?.

Granted this is a subjective thing but I?m curious if this pilot wrote the airplane up for potential structural damage...

The problem is most folks have never experienced that kind of turbulence, so there really isn?t a common frame of reference to decide what is moderate, severe, or extreme....

Some time back the view out the window suggested some unusual weather behavior. Since I live in Boulder, one of the places where mountain wave activity is very soarable, that was worth following up. I forget the winds aloft but they were impressive. The important thing was the pireps. An F-15 reported extreme turbulence and so did a Boeing Heavy.

Got to say, those got my attention.

Dave
 
yes

My point is still that the level of intensity is still subjective; extreme turbulence in a 172 is quite different than in a 747...

At work, they are trying to integrate some of the newer aircraft's technology, ie acceleration sensors, to quantify, objectively, levels of turbulence...hope they get it working. It work give a much more accurate indication of turbulence level than relying on each individuals perception...
 
Wow, Carl, thanks for posting that. I use Skew-T all the time, but there is way more here in the fine print than I knew.

Thanks

One of the problems with some of the "free" tutorials you can get on the Internet is that they are not presented from a pilot's perspective. That's why as a CFI I created my own 3 hr program and went on the road and taught a weekend workshop to pilots for over a decade. You need to understand how to read the diagram with respect to things like cloud tops, icing, turbulence, thunderstorm potential, non-convective LLWS, etc. It's really hard to find this kind of information all in one place. So I spent about 2,000 hours and created my own. There's a right way and wrong way to teach this to pilots.
 
I was thinking the same; to steal a line from Blazing Saddles, that looks like authentic frontier gibberish to me!

LOL! Once you unlock its secrets, you won't want to leave home without it! In a single diagram you can drill down and analyze every form of adverse weather that pilots care about. Pretty amazing stuff.
 
I wish I knew Skew-T... need more help. It's always been a mystery. Post some more.

The real reason I use the Skew-T diagram isn't to unlock its mysteries, instead, I use it as a canvas to teach pilots about weather. In order to learn how to use the diagram, you need to understand (well) the basic principles of weather...what causes turbulence, what causes icing, what causes non-convective LLWS, etc. And after the class, you not only understand how to use the diagram, but you secretly have learn a ton about weather.
 
My point is still that the level of intensity is still subjective; extreme turbulence in a 172 is quite different than in a 747...

At work, they are trying to integrate some of the newer aircraft's technology, ie acceleration sensors, to quantify, objectively, levels of turbulence...hope they get it working. It work give a much more accurate indication of turbulence level than relying on each individuals perception...

Even better, GPS occultation is one of the promising technologies for determining that turbulence is present.
 
I saw a brief presentation at Oshkosh last summer. It?s definitely a Swiss Army knife that I want to learn more about.

Don
 
I always wonder about the ?extreme turbulence? pireps.

By definition, this means that ?the aircraft is practically impossible to control and may cause structural damage?.

Granted this is a subjective thing but I?m curious if this pilot wrote the airplane up for potential structural damage...

The problem is most folks have never experienced that kind of turbulence, so there really isn?t a common frame of reference to decide what is moderate, severe, or extreme....

Yes if a airplane wrote up extreme turbulence at the airlines there would be a fleet of ambulances waiting and a trip to the hangar.
 
Pilotworkshops introduced a Skew-T lesson series. I just finished it about 2 weeks ago. Not plugging their product, but I found it way full of good info, but pilot oriented, not weather guy oriented. Takes you from zero to Skew-T hero - its 3hrs long but took me about 2 weeks to go thru, sitting by the fire pit with a beer. So much info, I had to go back to various modules and take notes once I started to get the gist. I'll probably go back thru the whole thing again cause I never catch the significance of specific comments until I'm done with something....I look at the charts often now, and get a good sense of whats going on along a specific route. Good news is that once you buy it you own it for life, so you can go back and review what you forgot.....

It was worth it for me anyway......

------
Oh, haha on me, I see Scott Dennstaedt posted above. He wrote the Skew-T series that Pilotworkshops now plugs......no I'm not a plant, and no I dont know Scott....and no I didnt read all the above comments before I posted.....
 
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I have gone through almost all the training videos Scott has on the site. Learned a ton of things. Still go back every now and then to refresh. I?m still no expert by any means but wwwaaaaaayyyyy further along the curve than when I started.
In my opinion, this has improved my safety much more than the piles of money I have stuck in backup systems....backup instruments, alernators, battery?s, etc.
Charlie
 
I bought Scott's skew T course on CD probably 10 years ago and I still dust it off from time to time to review It is like new technology. I can understand and use about 10% of its capability. But that 10% is mighty helpful- finding the layers, freezing levels, cloud bases and tops, and instability.
 
Scott,

Doesn't your app interpret the skew-T for dummies like me? Or that that just data from the weather folks that you put in a visual form?

I did some flying in the NE and mountain area and the ability to see the weather picture that quickly over your route is amazing; probably one of the best safety feature we've had recently.

Paul
 
I bought Scott's skew T course on CD probably 10 years ago and I still dust it off from time to time to review It is like new technology. I can understand and use about 10% of its capability. But that 10% is mighty helpful- finding the layers, freezing levels, cloud bases and tops, and instability.

Thanks Chris...it's like some of those fancy TV remotes you get...you really never learn how to use most of those buttons and features, but those you do use are essential.
 
Doesn't your app interpret the skew-T for dummies like me? Or that that just data from the weather folks that you put in a visual form?

I did some flying in the NE and mountain area and the ability to see the weather picture that quickly over your route is amazing; probably one of the best safety feature we've had recently.

Paul,

Thanks for that feedback. Everyone says the app greatly simplifies the preflight weather analysis to the point of feeling like you are cheating somehow.

The app displays some of the information you'll get on the Skew-T in the profile and meteogram views like clouds, wind and freezing level. However, there's so much more on the Skew-T that's hard to visualize any other way. For example, lapse rates. That's very hard to show on a profile view. You can contour something like potential temperature (theta-e). When it's changing rapidly, there's an inversion...otherwise, the lapse rate is large (I don't expect most to know what I'm talking about here).
 
OK, I need a Christmas study course. How to get Scott's Skew-T course?
and

Same here - where can I get this? As a newly minted IFR pilot I'm wanting to learn as much as I can about weather conditions and forecasting.

Steve and Greg,

I stopped selling my program on CD-ROM...just way too many bad experiences with Adobe Flash and CDs. So, if you are a subscriber of AvWxWorkshops.com you can get a discount of 15% since the Skew-T program is a premium workshop. As a member you'll get access to nearly 80 basic (bite-sized) workshops (including 17 that are Skew-T Tips) and the WeatherSpork app. Once a subscriber, you can purchase the workshop for online viewing only. But it'll give you the best experience and when I make updates, you get them for free.
 
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