If you have a four dimensional array, as you indicate, then the contents of Q are the humidity at corresponding Lon, Lat, Level, and Time. I.e. For your first longitude, first latitude, first level, and first time, the humidity can be found in Q(1,1,1,1).
In order to plot a countor of humidity at the different settings you're going to need to define what those other values are. The size of Q indicates that you should have 25 longitudes, 41 latitudes, 6 levels, and 168 times.
Once you define those then we can talk about making the contour plot.
