Coming on to an old thread...I'm trying to figure out the surface analysis thing for the Great Lakes as well.

As a broader solution (not just Great Lakes), it would be great to get the WPC conus surface analysis and/or forecasts in Expedition.  See https://www.wpc.ncep.noaa.gov/#page=frt. 

Those are clearly not Mercator projections though.  Does anyone have any hints on the settings I could use to import them manually?  I've tried a bunch of different settings but haven't found a solution that works.  I'm not sure if it is not possible or if I just don't understand projections well enough.

I've successfully imported the OPC's "USA Midwest" surface analysis (see https://ocean.weather.gov/UA/USA_Mid_West.gif), which appears to be on a Mercator projection.  That would be a cool one to fetch automatically.