Skew T

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Here is the current Skew T diagram for the RDU area. I'm trying to learn how to understand the diagram as a pilot, not as a meteorologist. I keep hearing how valuable the information is.

With that in mind, the scenario is that I am at an FBO en route back to RDU and am making a final decision on my IFR flight. I am also going to be looking at other briefing items (METAR, TAF, Convective Sigmets, etc) so I really don't want to spend a disproportionate amount of time focused on just one piece.

With that in mind, what are the important items I should be able to glean from it in say, 5 minutes (beyond the obvious "duh" that I might well have clouds where the temperature and dewpoint come close together)? And please point out where they are on the chart.
 

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The area around 10000 feet where the dewpoint drops off steeply for the second time (and there is a slight inversion) is the top of the haze layer, cruise about 10,000 feet and dodge the buildups. You'll also notice the wind picks up at this altitude (right side)

What you are looking for in the summer (usually) is instability and then the top of the haze layer. Below the haze layer you notice the red line goes sharply left indicating instability and then around 10k there is a little bit of an inversion. A strong inversion will cap the development of storms. Today we have some pop-up CB's but nothing too strong

That's my best answer anyway :yesnod:
 
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Look at the index #s on the upper right...
top two CAPE that high means you're unstable and generally prone to convection. Not sure which CAPE it is, if it's sfc CAPE or most unstable layer CAPE. Makes a difference. sfc CAPE would mean you're pretty much ready to have convection or already are. Most unstable layer could still fail to be lifted over a less unstable layer below.
CIN is convective inhibition. 0 means there is no stable layer or no cap present to surpress convection.

This is a good summer pop-up storm sounding. Absolutely zero low level wind too.

on edit:
You can't just get info from one thing, as you said, but skew-t's are an important tool in the toolbox. I would expect scattered pop-up storms until peak heating is finished, then convection weakening as CIN builds. (Given that I haven't looked at ANY other weather info in that area...)
 
I will put in a plug for ScottD's teaching product on the Skew-T diagrams. www.AvWxWorkshops.com is the source for finding this. He also has an excellent YouTube video explaining the basics.

If you are fortunate enough to attend one of Scott's live events, most of one of the two days during the seminar is spent on teaching and using these diagrams.
 
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I will put in a plug for ScottD's teaching product on the Skew-T diagrams. AvWorkshops.com is the source for finding this. He also has an excellent YouTube video explaining the basics.

If you are fortunate enough to attend one of Scott's live events, most of one of the two days during the seminar is spent on teaching and using these diagrams.

Yup. In lieu of a meteorology degree, Scott's workshops are TAILORED for aviation. Very good investment.
 
I will put in a plug for ScottD's teaching product on the Skew-T diagrams. www.AvWxWorkshops.com is the source for finding this. He also has an excellent YouTube video explaining the basics.
Absolutely, but here's the problem: the Skew-T has been lauded as the greatest thing since sliced bread for pilots. If it is and that's not just hype, it should be easy enough for Joe Pilot to learn to read them without Scott's course.

I'm thinking very seriously about Scott's course. The problem is that even his various articles in aviation magazines tend to be too technical for me and I'm not yet convinced that it's worth it for this. That's the whole reason I asked the question - to see if pilots are indeed finding it valuable.
 
Look at the index #s on the upper right...
top two CAPE that high means you're unstable and generally prone to convection. Not sure which CAPE it is, if it's sfc CAPE or most unstable layer CAPE. Makes a difference. sfc CAPE would mean you're pretty much ready to have convection or already are. Most unstable layer could still fail to be lifted over a less unstable layer below.
CIN is convective inhibition. 0 means there is no stable layer or no cap present to surpress convection.

This is a good summer pop-up storm sounding. Absolutely zero low level wind too.

on edit:
You can't just get info from one thing, as you said, but skew-t's are an important tool in the toolbox. I would expect scattered pop-up storms until peak heating is finished, then convection weakening as CIN builds. (Given that I haven't looked at ANY other weather info in that area...)
Thanks James. The weather service has a simplified version of the soundings (non-Java) that doesn't even list the CAPE LFC or LCL numbers, leaving us to look at the graphic and figure it out. I have some concept of how that's done, but I'm still not sure the CAPE is telling me any more than the simpler Convective Sigmet or Convective Outlook.

Yes, I noticed the very large CAPE number. As I understand it, anything above 1000 signifies a thunderstorm potential; about 2000 or so severe storms). The Convective Outlook for the same period indicated a potential for thunderstorms but not of the sever kind, which was closer to the reality that occurred.
 
The area around 10000 feet where the dewpoint drops off steeply for the second time (and there is a slight inversion) is the top of the haze layer, cruise about 10,000 feet and dodge the buildups. You'll also notice the wind picks up at this altitude (right side)

What you are looking for in the summer (usually) is instability and then the top of the haze layer. Below the haze layer you notice the red line goes sharply left indicating instability and then around 10k there is a little bit of an inversion. A strong inversion will cap the development of storms. Today we have some pop-up CB's but nothing too strong

That's my best answer anyway :yesnod:
That's good. That's pretty much what ended up occurring yesterday evening. Want to sit down with me at the club and show me how you look at them?
 
A buddy of mine retired from the NWS (meteorologist) a couple years ago. He keeps threatening to teach me how to read them. I'll have to take him up on it some day. The FAA Glider Flying Handbook spends a chapter (I think) on SkewT charts. If I follow along, I can figure them out, but then forget almost immediately.

Reading them and interpreting them aren't necessarily the same thing.
 
Thanks James. The weather service has a simplified version of the soundings (non-Java) that doesn't even list the CAPE LFC or LCL numbers, leaving us to look at the graphic and figure it out. I have some concept of how that's done, but I'm still not sure the CAPE is telling me any more than the simpler Convective Sigmet or Convective Outlook.

Yes, I noticed the very large CAPE number. As I understand it, anything above 1000 signifies a thunderstorm potential; about 2000 or so severe storms). The Convective Outlook for the same period indicated a potential for thunderstorms but not of the sever kind, which was closer to the reality that occurred.

CAPE is just another tool in the tool box. You're already well ahead of the game knowing what you know.

Don't rely on absolute #s on CAPE. I've seen tornadic supercells w/ CAPE < 500. In fact, here's a paper on low CAPE supercells. Always remember it's POTENTIAL energy. It's not realized energy until it happens.

on edit... just found a paper for you about low CAPE supercells:
http://www.spc.noaa.gov/publications/guyer/weakcape.pdf
 
Absolutely, but here's the problem: the Skew-T has been lauded as the greatest thing since sliced bread for pilots. If it is and that's not just hype, it should be easy enough for Joe Pilot to learn to read them without Scott's course.

I'm thinking very seriously about Scott's course. The problem is that even his various articles in aviation magazines tend to be too technical for me and I'm not yet convinced that it's worth it for this. That's the whole reason I asked the question - to see if pilots are indeed finding it valuable.
It is, Mark, I've never been critical of you, but that's like saying you can be a banker without learning to add.

Seriously. Who are you kidding.

Nothing here needs be intuitively obvious. Weather is complex Learn parcel theory. You'll be a better airman for it. I can't even begin to explain to you what CAPE really is, without you first understanding the lifted parcel.

As to your OP SkewT, I can tell you where the layers likely are and that the tops were about 10,000.....

Your insistence on "it should be obvious" is like saying, "I don't need to study engineering, it's too occult, because it should be obvious."
 
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If I follow along, I can figure them out, but then forget almost immediately.

Reading them and interpreting them aren't necessarily the same thing.

It is like learning to fly. Takes practice. Spend a couple of minutes looking at them in the morning then note what weather occurs in the afternoon.

Nothing here needs be intuitively obvious. Weather is complex Learn parcel theory. You'll be a better airman for it. I can't even begin to explain to you what CAPE really is, without you first understanding the lifted parcel.

It is intimidating, but it's not terribly difficult, (unless you break it all the way down to Quasi-geostrophic theory... YUCK).

COMET modules are a great start.
register here: (free)
https://www.meted.ucar.edu/registra...F%2Fwww.meted.ucar.edu%2Fmesoprim%2Fskewt%2F&

skew-t module is here:
https://www.meted.ucar.edu/registra...F%2Fwww.meted.ucar.edu%2Fmesoprim%2Fskewt%2F&
 
The atmosphere is capped right around the 800mb level - no thunderstorms today, huh?
 
It is, Mark, I've never been critical of you, but that's like saying you can be a banker without learning to add.
The non-sequitur about banking aside, I can add just fine. Even do a bit of algebra. It's calculus while in an FBO trying to make an intelligent decision on the last leg of a flight home where I'm having some difficulty.

Nothing here needs be intuitively obvious. Weather is complex Learn parcel theory. You'll be a better airman for it. I can't even begin to explain to you what CAPE really is, without you first understanding the lifted parcel.
You mean the comparison the Skew T does between the behavior of actual temperature and dewpoint at various altitudes and the behavior of a theoretical parcel of air that will follow the dry adiabatic cooling rate until saturated and then follow the most adiabat? And how that comparison tells us about the degree of stability of the air due to the tendency of the parcel to either rise or fall?

As to your OP SkewT, I can tell you where the layers likely are and that the tops were about 10,000.....
...and they are and why?

Your insistence on "it should be obvious" is like saying, "I don't need to study engineering, it's too occult, because it should be obvious."
Perhaps you can locate where exactly I said, let alone insisted, that it should be obvious or intuitive. I'm pretty sure I used the word "obvious" once - to describe the nice red and blue temp/dewpoint lines and how they come together and move apart. To use your type of analogy, to state that a 6-ft circumference rock in the middle of the road is obvious is not equivalent to a statement that particle theory should also be as obvious.

OTOH, my real statement "what are the important items I should be able to glean from it in say, 5 minutes" is what I'm looking for. I'm looking for efficiency and value, not obviousness.
 
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The atmosphere is capped right around the 800mb level - no thunderstorms today, huh?
Can you explain that with reference to the chart? What is shown at that level that tells you this?

BTW,

KRDU 182008Z 23009KT 8SM TS SCT050CB BKN080 BKN200 30/22 A3009
 
The non-sequitur about banking aside, I can add just fine. Even do a bit of algebra. It's calculus while in an FBO trying to make an intelligent decision on the last leg of a flight home where I'm having some difficulty.

You mean the comparison the Skew T does between the behavior of actual temperature and dewpoint at various altitudes and the behavior of a theoretical parcel of air that will follow the dry adiabatic cooling rate until saturated and then follow the most adiabat? And how that comparison tells us about the degree of stability of the air due to the tendency of the parcel to either rise or fall?

...and they are and why?
sigh.
Perhaps you can locate where exactly I said, let alone insisted, that it should be obvious or intuitive. I'm pretty sure I used the word "obvious" once - to describe the nice red and blue temp/dewpoint lines and how they come together and move apart. To use your type of analogy, to state that a 6-ft circumference rock in the middle of the road is obvious is not equivalent to a statement that particle theory should also be as obvious.

OTOH, my real statement "what are the important items I should be able to glean from it in say, 5 minutes" is what I'm looking for. I'm looking for efficiency and value, not obviousness.
You have to learn parcel theory, or the Skew T is useless, Mark. It's just like you have to take torts to think like an attorney, or patho-physiology to think like a doctor.
To use your type of analogy, to state that a 6-ft circumference rock in the middle of the road is obvious is not equivalent to a statement that particle theory should also be as obvious.
PARCEL theory, Mark. PARCEL.

But you can't refuse to take the pre-requisite course, when you need to learn the NAME of the course. You can't understand what you need to, and refuse to take the basics. How can you know what you don't know?

No you are not being asked to become a meteorologist. Far from it. So take the first course taught in the university for meterology majors. Just don't confuse that with becoming a weatherman. And no, it's not free.

(No pecuniary interest with Scott. Just an early purchaser of his educational tools).
 
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looks like an OK soaring day, not great but OK
 
A little word of advice. If you don't know how to use it...don't. I've seen way too many pilots come up with some really, really bad interpretations because they *think* they understand it. This is not one of those tools that should be self taught.
I won't. Unless and until I can use it as a semi-accurate predictive tool (make a prediction on the ground; see how it turns out; rinse and repeat), I wouldn't dream of relying on it.
 
Dontcha just love it. Another airman who is loathe to spend a dime on education. This is the kernel off GA's problem, right here. Everyone is telling you it's a great value. But he wants it for free. JUST not possible.

You can get the same content, in 10 weeks, two hours a week, at ERAU's Aviation Weather 101...which is not, by comparison, a good value.

"If it's so great it should be obvious to Joe Pilot" (not)!
So I guess you'll just wonder whether or not that last leg will be doable....now understanding parcel theory, PLUS the competent use of the tool won't guarantee you make it, but NOT understanding the tool does guarantee that you will make errors you will not otherwise make....

sigh.
 
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No you are not being asked to become a meteorologist. Far from it. So take the first course taught in the university for meterology majors. Just don't confuse that with becoming a weatherman. And no, it's not free.

(No pecuniary interest with Scott. Just an early purchaser of his educational tools).
Sigh.

Here's my problem. I spend a lot on educational things. Always have. Always will. A lot of them have turned out to be cost without benefit and the most common denominator seems to be that the less available public information is about it, the less value there is to it. Call it one of cornerstones of my brand of cynicism but it's served me well both personally and professionally.

Notice this thread, including your response. Not one person has answered my basic question to show me what they gleaned from the chart I posted and what on the chart tells them that.

I'm not asking for a course; just collecting some basic evidence that pilots are in fact using it and getting reliable information from it in a reasonable time frame for making a decision. So far, interestingly, I have gotten none, with some even telling me I'm wrong for even asking.

Since you're using various businesses as an example, let's think of it in terms of the phrase "due diligence." I'm, doing my due diligence on cost/benefit before deciding whether I will take the plunge.
 
Oh goody. People telling me they think it's valuable is a wonderful substitute for evidence.

If anything the barrage of "you shouldn't eve ask" tells me people aren't finding it all that valuable.


Snake oil anyone?
 
..... Not one person has answered my basic question to show me what they gleaned from the chart I posted and what on the chart tells them that.
......
We have told you over and over, that we cannot answer that without understanding parcel theory.

Now, to put on my professor hat:

"No, it would be pointless for you to enroll in my course without the prerequisite. No I will not message the dean to allow that enrollment because the effort would be useless".

Your alternative is to enroll online in ERAU aviation weather 101 ( I think they still offer it). I have mentioned that, prior in this string. But IMO Scott's stuff is superior.

So I am left to conclude that you are not willing to invest anything, and that you will continue to wonder if that last leg is make-able. Mark, remind me regard your subsequent posts differently than I have in the past.

A real student would view the puzzlement about the Skew T as a signal that more improvement in the area of understanding weather, was indicated. Latching on to the Skew T itself....well it's as Scott says, and for your safety, PLEASE DON'T ATTEMPT TO USE IT.

So like Ronnie Reagan, you want business to determine the value of education. guess what, you just did determine it wasn't worth your while. Be CAREFUL out there.
 
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guess what, you just did determine it wasn't worth your while.
Your only correct analysis of me and this issue so far, Bruce. I'll continue to make weather decisions based on the information I used over the past 20 years.

PS. Kindly save your condescending tone for the Red Board.
 
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Scott, thank you. That last post was very helpful. And I duly note that you are not trying to "sell" me with the haughty condescension I am receiving elsewhere (which generally reflects more on the speaker than the recipient but, being only human, the "Red Board" style posts had the effect of turning me off to the concept completely).

I understand that no one tool should be viewed in isolation. I'm just trying to determine whether the additional information provided will be useful enough for me to learn it properly. For right now, that answer is "no" but it might change in the future.

BTW, I should mention that I did not look at the TAF and METAR for the period until almost 2 days later. In each case I pulled both the Skew-T and the historical METAR just minutes before posting them.
 
That's good. That's pretty much what ended up occurring yesterday evening. Want to sit down with me at the club and show me how you look at them?

Would be happy to.. i'll be around this weekend I think

As others have said Scott's courses are very helpful.
 
Mark,

You might consider buying the following book from www.soarbooks.com:

Thermals, Rolf Hertenstein

It is a good book, not textbook size, but easy to read and understand, and spends all of its time looking at Skew T's. There is of course a bend towards soaring weather however it will give you a good start in learning how to read the sounding and see what it is telling you. Find how to predict cumulus cloudbase and top, freezing levels, inversions, see if the atmosphere is capped for thunderstorms, predict if the cumulus field will develop into overcast or stay scattered, etc etc. only 18.95, I found it very helpful when I was first learning to soar and it also set me down the path of starting to understand the Skew T much better.
 
Mark,

You might consider buying the following book from www.soarbooks.com:

Thermals, Rolf Hertenstein

It is a good book, not textbook size, but easy to read and understand, and spends all of its time looking at Skew T's. There is of course a bend towards soaring weather however it will give you a good start in learning how to read the sounding and see what it is telling you. Find how to predict cumulus cloudbase and top, freezing levels, inversions, see if the atmosphere is capped for thunderstorms, predict if the cumulus field will develop into overcast or stay scattered, etc etc. only 18.95, I found it very helpful when I was first learning to soar and it also set me down the path of starting to understand the Skew T much better.
Thanks Tony.

Another interesting introductory source I fell across during my inquiries is a program Ed Williams did called "Weather in the Vertical." The PDF of a PowerPoint and the mp3 of the live presentation are available on his website. Still going through that one but it seems interesting (and suggests Bruce may need to read up a little more on Parcel Theory).
 
Your only correct analysis of me and this issue so far, Bruce. I'll continue to make weather decisions based on the information I used over the past 20 years.

PS. Kindly save your condescending tone for the Red Board.
Just calling it the way it is.
 
With that in mind, what are the important items I should be able to glean from it in say, 5 minutes (beyond the obvious "duh" that I might well have clouds where the temperature and dewpoint come close together)? And please point out where they are on the chart.

For the VFR flying I do...In less than five minutes. I look for Cloud Base, Cloud Top, Inversions, Freezing Level and Winds. If temp dew point spread is less than 5C I expect hazy conditions. Less than 3C I expect clouds/fog. I fly above inversions for better visibility/cleaner air/usually less turbulence/possibly better winds. I enjoy learning about wx, watching it from the ground and flying in it.
 
For the VFR flying I do...In less than five minutes. I look for Cloud Base, Cloud Top, Inversions, Freezing Level and Winds. If temp dew point spread is less than 5C I expect hazy conditions. Less than 3C I expect clouds/fog. I fly above inversions for better visibility/cleaner air/usually less turbulence/possibly better winds. I enjoy learning about wx, watching it from the ground and flying in it.
Thank you Wayne. Looking at the chart I can see exactly what you are saying and where to find it. Fortunately in my research I was able to come across a few good posts and sites dealing with the subject, although there is clearly a benefit to programs like Scott's which are more geared to pilots than to meteorologists.
 
Edit: Ah, never mind. No reason to come down to your level.
Unbelievable. In six years I've never been critical of you. Then I am, just ONCE, just ONCE, and you can't take it.


"I don't want $40 for no learning"
Please stay in wherever you live an out of the 12-16Ks where I live.
 
Unbelievable. In six years I've never been critical of you. Then I am, just ONCE, just ONCE, and you can't take it.

Yeah, probably because you were a complete toolbag about it.

You opened with an anecdote about math-illiterate bankers, and "who are you kidding?"

You demanded (repeatedly) that OP learn "parcel theory", but did not provide any sources to learn parcel theory, or even peel off a slice of your imputedly vast knowledge on the subject to encourage him to do so.

When OP was unable to see your educational path and its associated payoffs, you lumped him in with a group of cheapass pilots who never spend a dime on education -- in a thread where the guy is asking for clues and trying to evaluate whether the investment will have any value to him.

You then offer to discount his future posts for not meeting your criteria of excellence, thus throwing ice water on any subsequent fruitful exchange.

Garnish liberally with your patented drama-queen "sigh", and you've got a recipe for "you know what? F skew-T anyway and I'm sorry I asked."

==

I was reading on the sidelines because I'm of a similar mind as OP about skew-T.

I live in an area not plagued by T-storms, but fly through those areas frequently enough. I have good tactical experience for staying clear of T-storms, but an additional forecasting tool would be handy for me.

I am always looking for new things to learn that will improve my flying, but I don't throw money at EVERY offering every time, because I am limited in what I can use right now. As such, I focus my educational time.

For example, I also have not personally invested in:

Tailwheel training
Acrobatics
Turbine/Jet type ratings
Formal simulator training at simcom or the like
Altitude chamber training

I have not done these because they do not TODAY offer a value for the type of flying I do, and I instead focus on things that do. For me, this is:

multi-engine dual
IFR dual
The APS online course
The ABS Bonanza and Baron online course
BPPP training

...the above in the last 12 months for me. It's not about the investment dollars, it's about value and relevance. There could be a $1 program that teaches every single thing about acrobatics, but I don't plan to do any just now, so there is no value there.

I have several times come back to Skew-T with interest, because it seems to offer some potential uses for my flying. Similar to OP, I've asked a few local weather bugs for the "high level" view of Skew-T, but none have showed me an example of where skew-T would provide me decisive information to improve the kind of flying I do.

I still believe there is potential. It's why I clicked on this thread. In order to capture my training dollars, though, I need a hint that it will be a useful tool in my toolbag, and not just a mathematical curiousity which sometimes shows an interesting result about convection -- ex post facto.

But man, dog-piling the dude for asking "will I get anything out of this course of study?" is pretty rotten. If the topic can't stand even that low level of questioning, it doesn't seem like a very robust topic to begin with.

So maybe the questions worth answering are:

1. Will Skew-T offer a tactical benefit in my weather brief? If so, in what sorts of conditions?

:dunno:
 
1. Will Skew-T offer a tactical benefit in my weather brief? If so, in what sorts of conditions?

:dunno:

Would you like a forecast of cloud bases + tops going out 24 hours and updated hourly? Like to know where the inversions are? top of the haze layer in the summer?
 
So maybe the questions worth answering are:

1. Will Skew-T offer a tactical benefit in my weather brief? If so, in what sorts of conditions?

:dunno:
Yeah. it will.

Find a warm nose in winter.
Avoid some of the heaviest ice in winter.
Avoid turbulence in summer.

But for it to do so you have to spend 4 hours learning parcel theory. 4 hours and about $50 bucks. As I was just informed by PM, I'm a horse's_ss. But it's the horse's_ss that doesnt' spend 4 hours and $50 bucks to learn a powerful new tool.

You can't know what you don't know. You both kinda remind me of a PVT ASEL I had once who wouldn't learn something that wasn't obviously necessary to learn.

I'm busy teaching the 135 operator in our building...not only to avoid turb., but find a way he can fly his customers (prohibited to be in known ice) in the winter. It's already saved him two flights.

All those threads about, "should I go?". How do you think we commented on them? Did we say, "well the redline goes here, and the blue line goes there, so we think you should go"?

*********
"Weeeeeeeeee don't need no steekin eddication." "just tell me what the lines mean".....well, we did, but that doesn't tell him how to interpret them.

That is the subject of a course. Scott basically gives ERAU aviation weather 101 (my apologies, Scott, you do a MUCH better job that that) in an internet format, and it VERY inexpensive.

Sigh.
 
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Spending ANY money on weather training is VERY worth it and a good investment. We operate in a dynamic environment and I'm really surprised at how little we are taught about that environment during primary training.

When I spent money to do a one-on-one training session with ScottD a few months ago, I learned a HUGE amount about how to do a good weather product review and planning for the flight.

To me, what I spent on the training was a pittance to the value I got out of it for that trip and future trips.

Investing in any quality training will always pay itself back.


@Bruce -- Remind me to explain the "Poopy Diaper Attitude" to you sometime.
 
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