@JeremyECrawford A spellcaster affected by invisibility casts a non-concentration spell; can he be counterspelled?
— Armando Doval (@armando_doval) June 8, 2017
Counterspell requires you to see the spellcaster you're countering. See its Casting Time entry. #DnD https://t.co/XG9EkkNNEU
— Jeremy Crawford (@JeremyECrawford) June 8, 2017