CNC-Dude:

In the "Great Northwest" (Southern Oregon on Agency Lake at 4,200 feet specifically) we have an old saying about the weather: "If you don't like the weather [now], just wait an hour . . .".

And that's the real truth. We can have a ridge of high pressure in place and then have a low pressure trough blow in (typically from the south and west) and the barometric pressure will drop like a rock in a matter of a couple of hours. With attendant changes in moisture and temperature, we can see our corrected altitude move my more that 1500 feet! That can sure impact the performance of a naturally aspirated (non-EFI) engine running on pump gas!

PS: The one offset we have to these local conditions is all the good oxygen put off by our forests. NHRA crew chiefs say they actually have to take that into account when racing at Seattle.

Last edited by russk; 10/16/09 08:21 PM.