Why Do Snowstorms Move Eastward, and What is a Jet Stream?

Last time, we talked about convection currents. What do you get when you cross convection currents and a rotating planet? Jet streams!

A convection current occurs when hot air rises away from a heat source, cools, gets denser, sinks back down towards the heat source, and repeats the cycle again.

Now, picture the Earth. The equator gets the most direct sunlight, and is therefore warmer than everywhere else. As a result, hot air moves away from the equator, cools, and then moves back towards the equator. You can think about it like a big, three-dimensional convection current. To us, those currents feel like wind (because they are).

Here’s the fun part: The earth is spinning! These convection currents rotate along with the earth, but end up moving slightly faster than the entire planet, so appear to move in the same direction earth is rotation (west to east). These currents, or jet streams, move many of the air masses and storms that create the weather patterns that make our seasons a little more interesting.

Because of the jet streams, big weather patterns, like snowstorms in the US, tend to move from west to east!

Source:

https://scijinks.gov/jet-stream/