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Meteorology (Weather)/pressure over mountains and/or high altitudes


QUESTION: I live in the Salt Lake City area, which is over 4,000 ft above sea level.  Also, very close are mountains that are about 10,000 ft tall.

I've been reading about adiabatic lapse rates, high and low pressures centers, etc.  I would like to know if living so high above sea level changes these basic properties?  For example, since I live at 4,000, why is it so hot in the summer?  And does the air pressure at this altitude differ from the air pressure that would exist at the same altitude and place if the earth were at sea level?

ANSWER: Hi Jim, I'll answer your questions one at a time.

1. The adiabatic lapse rates do not change with elevation.

2. While I don't know the specifics of your area, dry air is a lot easier to heat up than moist air and with ample solar radiation, it could warm quickly.

3. I'm not sure what you're asking on your last question, but if I understand it correctly, yes, air pressure could vary place to place at the same elevation.

Hope this helps.

---------- FOLLOW-UP ----------

QUESTION: Thanks so much.

You said, "I'm not sure what you're asking on your last question, but if I understand it correctly, yes, air pressure could vary place to place at the same elevation."

Let me ask it a different way: Here's an idealized thought experiment.:

I live in Salt Lake at 4,000 ft.  Assume I am currently under a High pressure zone, with subsiding air.  Air pressure is X.

With my magic wand, I remove enough earth to put Salt Lake at sea level, still under the same conditions as before( under a High.)  I take a balloon from my new Salt Lake City location, at sea level, up to 4,000 ft, and measure this pressure, call it Y.  

Is the air pressure X the same as air pressure Y?  .....note, these two readings are at the same altitude, under a High, everything else being equal.

My answer would be 'No'--- the pressure would be higher in the first scenario, because:  The subsiding air over a Salt Lake City, at 4,000 ft, leaves less space for the subsiding air to get 'squeezed' into compared to the second scenario. So, under dynamic conditions, such as a High (or a Low) the air pressure difference would not be due simply to altitude.

(Now, I'm not certain if this would apply to a Low: since there is no "ceiling", there might not be the same "squeezing" effect under a Low (the air is rising. )

If I were were not under a High or a Low, I would say, then, the two air pressure reading would be the same.

What do you think the two pressure would be in the experiment I imagined, under a High and then under a Low, or under neither a High or a Low?

Thanks for your help.

If I understand correctly, I'd say no. I'd agree with your explanation as well. As for your pressure question, assuming a surface pressure of 1000 mb, the pressure at 4000 ft would be 861 mb, making the classical assumption that pressure decreases exponentially with height. You may want to look up the Hydrostatic Equation if you haven't already.

Hope this helps.

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David Moran


I can answer questions about radar and large scale meteorology. If a question looks like homework, I won't answer it.


I have been a forecaster for many years with a specialty in severe weather.

Full Member, American Meteorological Society

BS in Meteorology, University of Oklahoma BA in Mathematics, University of Oklahoma

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