I have no predictions about how it plays out, but it's very easy to see this thing falling apart. And given the difficulties that Boehner's team has had counting votes so far, it wouldn't be a shock to see it collapse during the vote.There's obviously a lot going on so budget stuff isn't getting a lot of play, but the fact that Republican Study Committee Chair Jim Jordan said he's going to oppose the extension could be a very big deal. The same things that I (and Stan Collender) were wondering about then still applies now: if Republicans don't have the votes to pass this thing, will Democrats bail them out? How many Republicans are willing to stand with John Boehner and against Tea Partiers?
As far as the numbers...on the last, two-week, extension, only six Republicans voted no, while the Democrats split 104/85. As Felicia Sonmez notes (see link above), 176 Republicans are RSC members, so if they all oppose the CR it's not going to pass. Even if they split evenly, a relatively small shift among Democrats could doom it. So again, I have no predictions, other than to just point out that this is a very volatile vote -- a quick swing against it is a strong possibility.
If they do manage to get the three-week extension done, it sure looks as if we're at the end of that particular road. Given that sooner or later there's eventually going to have to be a deal, I suppose it's not impossible that one will be reached to prevent a shutdown in three weeks, but it's sure hard to see how that happens.