Sooooo.....
I've got a nifty altimeter watch (HighGear Altera) that I enjoy using on the trail. I know it requires recalibrating regularly because as weather pressure systems come in it affects the calibration.

It also has a barometer which I know, in theory, can help me predict an incoming storm. You can view either the pressure in either "in Mg" or watch a low res chart for the last few hours (not sure of the actual time scale).

How would I use this to predict the weather on my upcoming hike along the southern section of the JMT + Whitney??

The scale ranges from about 28.00 to about 31.00 Hg, or inches of mercury. In very simplified terms, a rapid fall in pressure—bout .10 or more in less than an hour- typically means a storms-a-commin. When the reading remains steady or starts to slowly climb during rain, it typically means fair weather is on it's way.

Edited by judach on 10/09/2009 09:01:34 MDT.

Thanks, that's easy to remember.

Edited by worth on 10/12/2009 19:48:36 MDT.