I'm in chilly northern California rather than a warm conference room in Los Angeles, but hey, at least my Wi-Fi is good and I'm keeping on eye on the TCA coverage.
To nobody's surprise, CBS' Nina Tassler confirmed what you've known all along: Three Rivers is canceled:
Yes, it's officially canceled. "We've all known each other long enough to know that when something is on 'hiatus,' it's code for something else.
Somebody asked if Moonlight might come back now that Alex O'loughlin is freed up. No, but they are looking for a new vehicle for Alex.
Interestingly while the fate of Three Rivers has been sealed, the coffin hasn't been sealed for Numb3rs. Apparently both Numb3rs and Medium are being considered for additional seasons. Of course that means the reverse is also true and that neither might be back next year.
Numb3rs had its order shortened to 16 episodes this season, and CBS reportedly has a lucrative syndication deal with Lifetime for Medium episodes (but the specifics of that deal are too murky for me to know whether additional episodes next year would benefit CBS in that deal).
Numb3rs fans who were fearful that the show wasn't coming back next year should still be fearful. But those who'd written it off completely might have the tiniest sliver of hope. On the other hand, I'd read this as a sign that the color-code for Medium might need to change in our renew/cancel index to reflect some danger of cancellation in May.