On SIGWX (significant weather) charts, what does **/** mean? On SIGWX charts, it shows pairs of symbols with, say, */** or **/**. I know what the symbols mean on either side, but why are there two, and what does the slash indicate?

Would love good resources that explain more, too.

Example chart here, from the FAA sample questions (caution: 37 MB download), Figure 20, over Southern California.

I’m also interested in knowing what a dot with R underneath means.
http://www.beyourowncaptain.com/downloads/files/Reading%20Prog%20Charts.pdf
http://aviationweather.gov/static/adds/docs/metars/wxSymbols_anno1.pdf

Asterisks are snow, dots are rain. The slash means a mixture of the two. 



The dot with an R under it is a substitution for the the thunderstorm symbol.



What you're looking at isn't a real SIGWX chart, it's a testing figure.