[Dakota]

A while back, there was a thread about cold weather wear for umpires, but I don't recall long-sleeved tee shirts or underarmor-type undershirt being discussed.

Assuming the color is proper (white with powder, e.g.) is it proper (ASA) to wear a long-sleeved tee shirt or other undershirt with a short-sleeved umpire shirt and no jacket?

By "proper" I mean official ASA, not would a local league or UIC allow it.