Fix position on text.
Fix position on text.

Position should be signed--not unsigned.

jrleeman/MetPy,dopplershift/MetPy,Unidata/MetPy,ahaberlie/MetPy,jrleeman/MetPy,deeplycloudy/MetPy,Unidata/MetPy,ShawnMurd/MetPy,ahill818/MetPy,ahaberlie/MetPy,dopplershift/MetPy