Are you flying this holiday season? Understanding turbulence can help you be a bit calmer on your flight. Tawana Andrew explains in the latest "Science Behind the Forecast."
Bill Burton: It's time for us to take a look at the Science Behind the Forecast, as I am joined by WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.
Tawana Andrew: Good morning. This one is inspired by all of the holiday travel going on right now.
BB: Yeah. And it's something I don't think anyone has ever really enjoyed. Matter of fact, I've never met a person that said, you know, I like turbulence, but it's an interesting topic. So what do we need to know about turbulence?
TA: Well, the National Weather Service defines turbulence as irregular motion of an aircraft in flight, especially when characterized by rapid up and down motion caused by rapid variation in atmospheric wind velocities. In English, it's just the plane is pushed up and down a lot by changing wind in the atmosphere.
BB: Things get really shook up.
TA: Basically. So it is caused by the changes in air pressure and wind speed that lead to changes in airflow around an aircraft. And the severity of turbulence is dependent on what instigates that atmospheric motion in the first place. So you can have turbulence from that is light turbulence, where you have a slight altitude change, there's moderate turbulence, severe turbulence is when you end up with more of those drastic changes in altitude and air speed, and there could be some minor loss of control with the aircraft. Extreme turbulence is rare, and this is when that aircraft can be tossed pretty violently, but that doesn't happen very often.
BB: Thankfully.
TA: Thankfully, turbulence has four main causes. The first one will be frontal turbulence. So this is where you end up near a cold front. There's some thunderstorms in the area, and you end up with a little bit more of the air masses interacting, causing friction, which leads to turbulence. There's also wind shear turbulence, and this is a lot of what we see in the winter months, especially. So when you have that change in wind speed or direction with height, you're going to end up with a lot of motion in the atmosphere. And you typically find wind shear and wind shear turbulence near areas of low pressure, jet streams or near temperature inversions. There's also mechanical turbulence, and this is the ones where you fly over a city or going into land, you feel things a little bit bumpy. That's typically mechanical turbulence, because this is caused by the friction between the air and the ground. So let's say you have air flowing over irregular terrain, or even cities, that causes eddies and turbulence in the lower levels of the atmosphere, and you get some of that vertical motion going on. So you can also have thermal turbulence, and this is what we see a lot on sunny and warm summer days, because the Earth's surface, it's heated unevenly by the sun, and we tend to see this in more urban areas or in areas that are sandy and rocky, since the vegetation is being heated differently than the sandy rocky areas or even asphalt. Now the the one that everyone kind of talks about is clear air turbulence, and this is defined as turbulence not associated with clouds at or above 15,000 feet. Now, contrary to the name, skies do not need to be clear of clouds for clear air turbulence to occur. Confusing, I know. But with it, though, it can occur near cirrus clouds or even close to some thunderstorms. Now, with clear air turbulence, this is typically associated with a change of wind speed that could be without altitude or horizontally. The thing is, with clear air turbulence, it can span a pretty large area. It's usually around 2000 feet deep, around 20 miles wide and around 50 miles long. So that's a lot of space. It is covered.
BB: That's definitely a lot of space.
TA: But in extreme situations, clear air turbulence has been known to be 500 miles wide, 1000 miles long and 10,000 feet thick.
BB: I'll pass on that, thank you.
TA: Same, same.
BB: There's a lot to take in when it comes to talking turbulence, but we have a better understanding of it now thanks to this edition of Science Behind the Forecast with WAVE 3 meteorologist Tawana Andrew. Thanks for the knowledge, Tawana.
TA: Of course.
