Dear MK:

You wrote:
> One phrase that bothers me is “on tomorrow” as in, “We will meet
> you on tomorrow.” My stance is that as an adverb, tomorrow, today
> and yesterday do not need prepositions in front. Is this correct?
>
Yes, you are correct. I wonder if that is a regional expression. I cannot say I have heard people say it much. “We will meet you tomorrow” is standard.

“Tomorrow” is technically an adverbial noun–like “tonight.” That means that it is a noun which can act as an adverb. While it can be used as a subject of a sentence as in “Tomorrow is a long time,” it is usually used adverbially just as you say. In that case, there is no need for a preposition.

The root meaning actually is a compound word formed from the prepositional phrase that already begins with “to”; you could argue that adding the preposition is not only awkward but redundant.

It could also be that this expression is a misreading or misunderstanding of the phrase “on the morrow,” which is perfectly fine English, though perhaps slightly old-fashioned.