Weather 101: Downslope flow = warmup! - Tucson News Now

Weather 101: Downslope flow = warmup!

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When the wind is out of the east, Tucson is about to warm up. Here's why!

The elevation in New Mexico is higher than the elevation here in Tucson. So, the air, when the wind is from the east, is originating in a zone with a higher elevation.

Illustrating downslope flow from New Mexico.

As air sinks to the lower elevations here in Tucson, it warms.

Basic principle of physics alert! Sinking air warms!!!

When you measure the atmosphere's thickness over a location, you are in essence measuring the distance between the ground and the edge of space.

At higher elevations, there is LESS air between the ground and the edge of the atmosphere.

Conversely, at lower elevations, there is MORE air between the ground and the edge of the atmosphere.

Air is made up of invisible particles, all of which weigh something. Added together, all other things equal, this weight of the air would be HIGHER in lower elevations and LOWER in higher elevations (see the paragraphs above).

Weight of the air is measured as atmospheric pressure. The more air you have pushing down on your area, the higher the atmospheric pressure.

Basic principle of physics alert! Higher pressure equates to warmer temperatures. Conversely, lower pressure equates to lower temperatures!!!

So, all else equal, in the image below, you can see that wind from New Mexico starts at a higher elevation and goes to a lower elevation as it enters southern Arizona. With the principles above in mind, this results in warming of the air from its original temperature in New Mexico to something higher when it gets here.

Illustrating the

 

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