Usually, we understand the adjective capace to mean "capable." 

Guarda che se non sei capace a dirgli di no, ti fai male!

Look, if you're not capable of telling him no, you'll hurt yourself!

Caption 20, Il Commissario Manara S1EP9 - Morte in paradiso - Part 1

 Play Caption

E... ma sai fare un po' di pasta fresca tu? Sei capace?

And... but do you know how to make a little fresh pasta? Are you capable?

Caption 11, Anna e Marika La pasta fresca

 Play Caption

But there is another, more colloquial way to use capace for predicting something, where it means something more akin to "possible." It's colloquial and used in central and southern Italy. Not everyone uses it with the subjunctive, but theoretically, the subjunctive should be used, since it has to do with uncertainty and is followed by che. 

From the horse's mouth: Tuscans, when asked, say you don't need the subjunctive, and you don't even need the verb (è). They say, Capace che piove, (it might very well rain) or even Capace piove, without the che!

È capace che Iside l'ammazza [sic: l'ammazzi].

It could be that Iside kills her.

Caption 2, Sposami EP 6 - Part 20

 Play Caption

Certainly, if you hang out in Tuscany, you will hear this usage of the word capace.  

banner PLACEHOLDER