Issue #89: TODO When adding the radar layers, the closest radar site's image needs to be the one on 'top', since that's the one that is going to be the most accurate where we are. This is still kludgey. What really needs to happen is that the radar images are composited in preprocessing so that the most inaccurate blips of precip are filtered out (as it is now we see precip indicated at the edge of radar sweeps that's not really happening)