In January 2001, a correspondent from New Orleans, Louisiana, wrote to the grammar website CCC.net's GrammarLogs, saying:
Recently, I have heard people at work using the phrases "on yesterday", "on tomorrow" or "on today" in their spoken language and written in memos. (i.e. I spoke to you about this on yesterday)
And the respondent from CCC.net replied:
That's a new one on me! Is it a regional expression, do you think? Odd how these things crop up from time to time
Since then, there have been quite a few comments on language forums about the use by some people of "on tomorrow", "on today", "on yesterday". And most of the commenters aren't happy, saying things like: "an aurally odious phrase", "Grates on my grammar nerves", "It's nails on a chalkboard to me".
A lot of the comments suggest that those who use this expression, both in speaking and writing, are mainly Afro-American, and it seems most prevalent in the deep South, especially in Georgia and Louisiana. And it seems to be being used by educated people like teachers and junior managers, not necessarily people who use Afro-American dialect (often called AAVE - Afro-American Vernacular English), or at least, not at work. Hoewever, it should be pointed out that quite a few of the negative comments also come from Afro-Americans.
Not being American, I'm a neutral bystander on this one, but rather liking quirky expressions, I was interested to know where it had come from.
Apart from these forum comments, however, there seems to be very little about this expression on the Internet. There is a blanket dismissal at WSU Common Errors (admittedly aimed at college students), and a slightly more understanding discussion at Grammarphobia (see links below), but apart from that, very little.
But when I started poking about in Google Books, I got some rather surprising results.