Tropical Upper Tropospheric Trough facts for kids

A Tropical Upper Tropospheric Trough (TUTT) is a special weather system found high up in the sky, over the warm parts of the Earth called the tropics. Think of a TUTT as a long, narrow area where the air pressure is a bit lower than the air around it. This "dip" in pressure happens very high up, about 12 kilometers (7.5 miles) above the ground.

What is a TUTT?

A TUTT is like a valley in the air pressure, but it's way up in the troposphere, which is the lowest part of Earth's atmosphere where most weather happens. The "upper tropospheric" part means it's located very high up, around 200 hPa (hectopascals) of pressure. This is much higher than the clouds you usually see!

How do TUTTs form?

TUTTs often form when strong winds from colder parts of the world, called the Westerlies, stretch out and reach into the tropics. They can also start near areas of high pressure, called anticyclones, that are also high up in the sky.

Unlike weather systems closer to the ground, TUTTs stay strong because of a special balance. Warm air sinks slowly inside them, which heats up the air. This warming helps to balance out the cooling that happens when heat escapes into space.

How do TUTTs affect weather?

TUTTs can have a big impact on tropical weather, especially on tropical storms and tropical disturbances (which are like baby storms).

Helping or Hurting Storms

Sometimes, TUTTs can bring a lot of "wind shear" over tropical storms. Wind shear means that the wind changes speed or direction very quickly over a short distance. If there's too much wind shear, it can tear a storm apart and stop it from growing stronger. So, in these cases, TUTTs can actually help prevent tropical cyclones from forming or getting worse.

But other times, TUTTs can actually help tropical storms! They can provide extra lift for the air near the storm's center, which helps the storm get stronger. They can also create a good "outflow channel" high in the sky. This means the storm can easily get rid of the air it pulls in, which helps it keep spinning and growing.

Other Effects

Under certain conditions, a TUTT can even grow into something called an "upper cold low." These are like mini-low-pressure systems high in the atmosphere that are colder than the air around them. When this happens, they can help make weather disturbances closer to the ground even stronger.