בוקר טוב אליהו

Etymology
Translates to "Good morning, Eliyahu!"

Dr. Rubik Rozental claims the phrase originated in Safed, where synagogue caretakers regularly woke up early a man named Eliyahu Salonim for Slichot prayers, saying "Good morning, Eliyahu!". With time, they used the same phrase to wake up any worshipper.

Now it's used to sarcastically comment a belated realization.

Phrase

 * 1)   no kidding, you don't say, no shit Sherlock