I have heard:
ahí (te) va
ahí me hablas mañana
which nevertheless is pronounced stressed a, forming rather than a hiatus, a diphthong. For sure it's not meant ay, the interjection, since demonstrative ahí makes sense. I wonder which is the geographical extension of this. I guess it's pretty much the same case as Argentinian/Uruguayan Spanish, where written accents are not always taken into account.
Suppose you want to write a novel, where you want somebody like hear saying ahí in this intonation. How do you write it?!