Wiktionary
top of the morning
phr. (context Ireland New England idiomatic archaic English) A generic greeting said to someone in the morning.
Wikipedia
Top of the Morning (book)
Top of the Morning: Inside the Cutthroat World of Morning TV is a 2013 non-fiction book by American journalist Brian Stelter. The book was first published on April 23, 2013 through Grand Central Publishing and centers on the world of morning television.