When it comes to barometric pressures the standard used in aviation is you lose one inch of pressure for every thousand feet of elevation above mean sea level, halfway between high and low tides.
High altitudes with high humidity and high air temps. really suck, huh Al
the bad thing about avaition weather reporting is they correct all of it to Instrument Standard atmosphere, which is 29.92 barometric pressure at mean sea level at 59.0 F with zero humidity
Las Vegas FAA reports for those airports around their will be corrected, not actual conditions, very misleading