Tropical Cyclone Rainfall: How Hard Can It Really Pour?

Author: Chris Nitsopoulos

Posted on: Wednesday, November 15th, 2023, 2:53:35 PM

Hey there, weather enthusiasts! With a tropical cyclone currently giving the US coastline a rough time, let's dive into a question that's as fascinating as it is complex: Just how much rain can a tropical cyclone dump per hour?

First off, let's bust a myth: there's no magic number for the max rainfall from a tropical cyclone. It's like asking how loud a rock concert can get – it varies! But, here’s the gist: The amount of rain a cyclone can whip up is tied to the water vapor in the atmosphere. Think of it like a sponge – the wetter the air, the more rain it can squeeze out.

Now, when weather folks talk about 'Precipitable Water', they're measuring how much water is hanging out in the air from the ground up to the sky. It's like measuring how much water you'd collect if you wrung out the atmosphere like a wet towel. In super humid tropical air, you could wring out up to 80mm of water!

But wait, there's more to this watery tale. The speed of the cyclone, its size, and even the wind shear (those pesky winds that blow at different speeds and directions) play a role. Slow, large, and steady cyclones can be real rainmakers.

Ever wondered why some places get way more rain from cyclones than others? It's all about the landscape. Mountains and hills are like nature's rain amplifiers. They take moist air, push it upwards, and voilà – heavy rainfall!

So, in a nutshell: Tropical cyclones can be relentless rain machines, but they're not the champions of downpours. That title goes to those booming afternoon thunderstorms that can unleash a torrent in minutes. But remember, cyclones are marathon runners, not sprinters – they can keep the rain coming for days on end.

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