[wxqc] Barometer Tweaking

[Charles Bland]

Me and my Peet Bros Weather Station live in the Sierra Nevada mountains at 3500 
ft AMSL.

My nearest airport with AWOS is at approximately 1700 ft AMSL. 
http://www.airnav.com/airport/O70

So, when I calibrate my barometer AT THE AIRPORT, then take it home, the 
reading always falls because of the elevation/air pressure change.

My question is, how do I adjust the AWOS reading at the airport to compensate 
for the elevation change to my house? Is there a ballpark number for air 
pressure change as you change elevation?

Chuck

p.s. a recent power outage here really goofed my station, so if you look the 
data quality page for me (CW4289) it is going to look REAL BAD. So, since my 
station battery died and I lost a bunch of data, I took the opportunity to 
solve my calibration problem on the barometer.