If you like being as cool as a cucumber, then you’ll enjoy this week’s segment of Weather Word of the Week! This week we’re discussing troughs. This is basically the opposite of a ridge in the upper atmosphere.

If you don’t know what a ridge is, check out last week’s Weather Word of the Week episode!

Feeding Trough for Cattle

No, not this type of trough. Although with just a quick glance at this photo, you can get an idea of how this atmospheric pattern got its name.

Still not following? Here is an actual snapshot of an upper level trough. It forms a rough U-shape in the atmosphere. It does indeed look similar to the container that holds cattle feed.

Example of an Upper Level Trough in the Atmosphere

What Weather Can You Expect When Under a Trough?

Two words that describe this weather pattern: cool and wet. Temperatures are normally below average and cooler thanks to the increase in cloud cover and rain chances. Troughs are simply an area in the atmosphere where the colder air is punching southward across a region.

Increased cloud cover blocks some of the sun’s incoming radiation keeping the temperatures cooler due to the presence of less sunshine.

The cooler air aloft can also increase the instability across the region. Cold air over warm air is unstable. If other ingredients are present, this setup can lead to the development of thunderstorms. The more storms, the cooler the air temperature.

Here’s an example of what the weather models look like for our area when we’re under the influence of a trough.

ECMWF Showing a Wet Pattern Caused by a Trough

Bottom line, if a trough is mentioned in your forecast, make sure you get the rain gear and umbrella ready. It will probably be wet in the days ahead.

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