The current altimeter setting at Phoenix Sky Harbor is 30.02. The current setting at my local airport here in the desert is 30.04 . Those
convert roughly to 1016 hPa. My MGBox is reporting 927 hPa. If that's a raw reading, it converts to 27.38 in., and I would be expecting
a hurricane coming this way. Actually, the lowest barometer ever recorded in Phoenix history was 29.20 inHg. (988.7 hPa). So I'm still trying
to understand an MGBox report of 927.

I had cervical spine surgery last week and  can't lift any weight, so photography is out of the question for a few weeks. That's why I have
all this time to chase these kinds of ghosts.

edit: Brent, thanks. That calculator worked - gave me a value that was close enough.