The GFA is a series of aviation weather maps showing what weather is forecast to affect aviation in a given region in the next twelve hours or so. It shows the centres of high and low pressure regions, the fronts, low visibility, clouds and precipitation, and dangerous weather, including icing and turbulence on a separate page. GFA stands for graphical area forecast (yes, the letters are in the wrong order). It replaced the FA (area forecast) about 15 years ago.
The GFA depicts provincial borders and has little circles for locations that have TAFs. (A TAF is forecast that covers the immediate area of an aerodrome). What takes some people a while to realize is that when you mouse over the little circle on the online GFA, text pops up to tell you the name of the place. It would be cooler if you could click on said text to see the latest TAF and METAR (which officially doesn't stand for anything), but I'll take what I can get.
I like to think of it as a little geography quiz. Pull up the GFA page, click on one of the regions, then choose any time. I recommend you pick one of the icing, turbulence and freezing level charts from the right column, because the left column clouds and weather charts can get so busy that you can't see the towns at all. Now try to name all the cities and towns represented by the circles, before you mouse over and see if you're right.
Sometimes one of the little circles doesn't show anything when you mouse over. I think it's usually when it's very close to a weather depiction. Some of the circles represent closed aerodromes where there is no observation or forecast, like Edmonton City Centre. They don't recode the GFA when they close an aerodrome, so it's a history quiz as well as a geography quiz.