Dealing with Turbulence on Flights

I have received several emails from folks asking about the meteorology of aircraft turbulence and how to avoid it if possible.   Where is the best place to get aviation turbulence forecasts?   

I don't claim to be an expert in this area, but let me give you some meteorological insights and practical advice.  Any pilots who read this can chime in.

Which Aircraft Should You Fly?

 Not all aircraft handle turbulence equally.   Bigger, heavier aircraft (like the Boeing 747, Airbus 380) don't bounce around as much.  Something called wing loading, the ratio of the weight of the aircraft to the wing area, has a large impact, with larger wing loading reducing turbulence.  Big, heavy aircraft have large wing loading, but so do some newer planes like the Airbus A320neo,

Some aircraft, like the Boeing 787 and the Airbus A320neo, have active systems that modulate control surfaces to reduce the bumps. 

So if you dislike turbulence  and can choose your aircraft, pick aircraft such as the Boeing 787 or Airbus A320neo if you can.

Where should you sit?

Generally, it is best to be over the wings, while the back of the aircraft is the worst. Over the wings you are near the aircraft's center of gravity and there is less lateral motion

When Should You Fly?

In general, the earlier the better.

Heating of the ground produces surface-based turbulence than can cause light to moderate turbulence in the lowest few thousand feet.  This is particularly noticeable when landing in arid regions during the summer.

Cumlus convection and thunderstorms are even more important and are often driven by surface heating.  Thus, there are much more of a problem latter in the day.

Aircraft Turbulence Apps

If you want to prepare yourself before flying, the are several free apps that allows you to view forecasts of aircraft turbulence.     

Most of these apps use the turbulence predictions made by the NOAA Aviation Weather Center--another reason why NOAA is important. 

 They start with NOAA global model predictions and then calculate parameters related to aviation turbulence, such as vertical wind shear.   A key forecast parameter related to turbulence aloft is called Turbulence Forecast Potential, with an example shown below from the website of turbulenceforecast.com).

A very easy to use aviation turbulence site in call Turbli.com.    You tell them what flight your are on and they provide a predicted timeline of turbulence on your flight (see below).

How good are these forecasts?   I have used them dozens of times and have examined some of their verification statistics.

They are useful, but far from perfect.  Why?

First, the NOAA global model model forecasts are imperfect, and yes, it is rated the fourth best in the world.  

Second, the resolution (13-km grid spacing) is too coarse to get fine-scale features and it does not do well with thunderstorms.

Third, the connection between predicted weather and turbulence is imperfect.

Fourth, the route (both horizontally and vertically) taken by aircraft are often different than assumed in the projections.

So consider it useful guidance.  

Finally, if you are interested in seeing where turblulence is being observed at a time, you can view pilot reports (call pireps), which are available in text or plotted on a map (see below).    

I find pireps very useful for research.  For example, I am doing an extensive examination of the meteorology of the LA wildfire and the severe turbulence reports suggest intense mountain wave activity.