# How do pilots and websites like Turbli accurately predict how much turbulence there will be in a flight?

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Every flight I go on I check Turbli before I do it to check out how much turbulence there will be (nervous flyer). Almost every single time I have checked it, it ends up being absurdly accurate. Then today when I was on a flight the pilot said that for the next 4 minutes there will be severe turbulence but after it should be smooth sailing. I looked at the clock and he was exactly right. How did he know? What instruments show this and how do they work?

In: 15

They (typically) use the NOAA forecasts (some other countries have their own models). I don’t know if the exact details of these forecasts are public, but there are most likely a few various things that NOAA factor in.

Turbulence is a complicated subject, and we can’t realistically do a perfect calculation (we can’t know the exact number of particles and their initial conditions to start with, and even if we could it would take a ridiculous amount of computing to do everything perfectly). We instead have various equations which can be shown to give good approximations for various different regimes (eg high altitude, low altitude).

The NOAA would combine all of their empirical data from various sources and throw it into their models which will use a variety of different calculations. Over time they improve on this by comparing their forecasts to what actually happened and tweaking their models.

Aircraft will communicate with control to update control on the weather, so if there is any turbulence that wasn’t forecast then this can be passed on to other aircraft.

See the Wikipedia pages on turbulence, Reynolds number, Richardson number, and Frontogenesis as examples of some of the maths that may be used in the models.

A pilot is in contact with an air traffic controller on the ground during the flight. Lots of other airplanes have probably flown through the same area and told the on ground controller about the turbulence. That gets forwarded to the next guy that has to go through then they tell the passengers if they want. So it’s all accurate cause it’s all real time.

This information also gets uploaded to various websites for weather models and is public information, which I assume that Turbli website uses

Take a look at the Aviation Weather Center website run by NOAA. Specifically:

[AIRMETs](https://aviationweather.gov/gairmet) (AIRman’s METeorological Information) which outline areas of weather that may be hazardous to pilots, including high and low level turbulence. The turbulence AIRMETs will have an altitude and severity associated with them.

[PIREPs](https://aviationweather.gov/airep) (Pilot Reports) which include reports made to ATC by pilots for various weather observations including turbulence which includes where the report was, when it was made, and how severe it was.

By looking at the AIRMET forecast for your flight you can see if you’re going to fly into one of the turbulence areas and be ready for it. If you look at the PIREPs you can see if other planes that have gone through that air before you have encountered turbulence.

Tangential: pilots have a different turbulence scale than most people. It might be slightly reassuring that your “severe turbulence” was probably considered moderate, at worst, by the pilot. Of course, the pilot knows this so he still calls it severe on the intercom.

In truly severe turbulence it’s completely impossible to walk around, and if you didn’t have your seatbelt on you’d hit the ceiling. Obviously, this is super extremely rare.

[Source](https://www.weather.gov/source/zhu/ZHU_Training_Page/turbulence_stuff/turbulence/turbulence.htm)