Is the size of hail on the ground any indication of the winds and updrafts of a thunderstorm?
The October 2018 issue of AOPA's "Flight Training" magazine provided the following illustration and comments.



A 24mph updraft will form ~1/4" hail, while a 98mph updraft will form
4" hail. 
Down drafts are usually about 1/2 the speed of the updraft
(due to a larger outer core area). 
When a pilot encounters a
downdraft, expect an updraft twice the speed to soon follow. 
The change will be a quick dramatic shear. 
Only about 10% of thunderstorms produce hail.