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  #1  
Old 12-09-2018, 01:04 PM
scottd scottd is offline
 
Join Date: Nov 2018
Location: Charlotte
Posts: 31
Exclamation The Skew-T and extreme turbulence

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.



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.



If you are not a Skew-T fanatic, make a New Year's resolution to become one!
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  #2  
Old 12-09-2018, 02:08 PM
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mike newall mike newall is offline
 
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Probably connected with this, yesterday.....



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..
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  #3  
Old 12-09-2018, 04:29 PM
AndrewR AndrewR is offline
 
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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?
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  #4  
Old 12-09-2018, 04:34 PM
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Steve Melton Steve Melton is offline
 
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I wish I knew Skew-T... need more help. It's always been a mystery. Post some more.
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  #5  
Old 12-09-2018, 06:05 PM
jbDC9 jbDC9 is offline
 
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Quote:
Originally Posted by AndrewR View Post
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!
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  #6  
Old 12-09-2018, 06:39 PM
rocketman1988 rocketman1988 is offline
 
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Default 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....
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  #7  
Old 12-09-2018, 06:45 PM
Paul K Paul K is offline
 
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Quote:
Originally Posted by RV8JD View Post
Carl, I thought I knew a lot about Skew-T. After looking at this, I don't know anything!
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  #8  
Old 12-09-2018, 08:11 PM
David Paule David Paule is offline
 
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Location: Boulder, CO
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Quote:
Originally Posted by rocketman1988 View Post
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
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  #9  
Old 12-09-2018, 09:09 PM
rocketman1988 rocketman1988 is offline
 
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Default 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...
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  #10  
Old 12-09-2018, 10:29 PM
scsmith scsmith is offline
 
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Quote:
Originally Posted by RV8JD View Post
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
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