Calm wind symbol not always concentric with cloud cover symbol

[sgdecker]

The existing example at
https://unidata.github.io/MetPy/latest/tutorials/declarative_tutorial.html#plot-surface-obs
demonstrates this issue.

Looking closely, you'll see some stations (such as in central WI where the temperature is 64) where the calm wind symbol is dead on, but others (such as in southeast KY where it is 70) where the calm wind symbol is not centered on the cloud symbol.

As in that example, my own plots demonstrate the same issue, and it seems somewhat random which stations are perfectly concentric and which are not.

[dopplershift]

I could have sworn there was an open issue on this somewhere, but I can't find it at all. This is known behavior from matplotlib related to how it renders. I think matplotlib/matplotlib#7233 is probably your best starting point if you want to understand.

TLDR; Nothing we can do AFAICT in MetPy, this has to be fixed in matplotlib.