How high pressure affects our weather

August 12, 2022
How high pressure affects our weather
Published: Aug. 12, 2022 at 5:42 PM CDT
Email This Link
Share on Pinterest
Share on LinkedIn

HASTINGS, Neb. (KSNB) - Lately you may have heard the term ‘ridge of high pressure’ used as we tolerate another week of hot summer temperatures. The opposite could be said for folks living on the east coast where there is currently a ‘trough of low pressure’ affecting them. But what does it all mean and how does it affect our weather here in Nebraska?

Looking at the a map of the United States in this video, you can see the big blue H in the middle of the map right over top of us. A ridge is formed in the jet stream around an upper level high. If you think of a hill or mountain ridge, it goes up, has a peak and then drops down on the other side. That’s what we see here with the jet stream. Under high pressure there is sinking air which warms as it goes from low to higher pressure toward the surface. Have you ever felt the valve stem on a bike tire after pumping it up? You have taken air from low to higher pressure and it heats up. Let’s now take a look at a low pressure trough. It can can be seen where there is a dip in the jet stream like this one over the southeastern U.S. Think of a feeding trough and how it dips down low inside. That’s one way of remembering it. Troughs are associated with rising air with cooler and often unsettled weather.

Another way ridges and troughs affect our weather is how they direct mid and upper level disturbances by the way of the jet stream. when there is a ridge over top a region, the showers and storms associated with disturbances ride up and over as the jet stream carries them along. Not only is it hot, but it can also be very dry under an area of high pressure. Troughs, on the other hand, usher in cooler and unsettled weather. Thankfully, this ridge will be weakening and replaced by a trough next week. That means cooler weather and rain chances are on the way.

Copyright 2022 KSNB. All rights reserved.