Snowfall, Freezing and Prozen Precipation
                  How Much Frozen Precipation Fell?

The flx files do not say how much snow or frozen precipitation fell
in the 3 hour period.  There is a variable, CPOFP, is the percentage
of frozen precipitation for one instant in time.  So you can only
estimate the frozen precipiation that fell in the 3 hour period.

Note that CPOFP is not a useful quantity when averaged.  You can't
get the snowfall by multiplying the average CPOFP and average precipitition.