Hi Brandon,
I too am looking to automate jpg exports from a Map Series and so far have nothing (admittedly I have wasted my time on this in a while) The only workaround I can think of is:
1) instead of using map series, create the extents of your maps manually and bookmark them
2) in python, loop through your bookmarks (setting the extent of your maps) and then export each one as jpeg
This is just a thought, and I have not tested / investigated the feasibility of it. If you try it, please let me know how it turns out for you.
Hope they just update the Arcpy module to handle this properly in the fall release of ArcGIS Pro (1.5)
Cheers,
Sean