The third vote will be on a cloture motion, to end debate on the bill.

If the Senate votes to end debate, the 30 hours needed before a final vote on the bill will start from 1 a.m. Wednesday. That means if the full 30 hours are needed, a vote could happen as early as 7 a.m. Thursday.

Or, a vote could come earlier — even today — if the two sides agree to speed up the process.

It could be in the interests of senators to agree to an earlier vote. After the 2013 spending bill is done, the Senate will move to the 2014 budget resolution, S.Con.Res. 8, and is pushing to finish that resolution this week — or, more likely, this weekend.

One Senate Republican suggested that the Senate should take up the budget when it returns from a two-week break that was scheduled to start this weekend. But Senate Majority Leader Harry ReidHarry Mason ReidDonald Trump is delivering on his promises and voters are noticing Danny Tarkanian wins Nevada GOP congressional primary McConnell cements his standing in GOP history MORE (D-Nev.) has insisted repeatedly that the budget will be done before the Senate leaves.

Reid often threatens weekend work, but doesn't carry out that threat nearly as often.

Fifty hours of debate are needed on the 2014 budget, which means weekend work for sure even if the Senate starts early Thursday morning. It's unclear how many amendments senators will want to attach to the budget, a factor that has the potential to extend the process considerably.

Democrats are partly hoping that a weekend schedule dissuades senators from offering endless amendments. But weekend work might not be enough to discourage Senate Republicans in particular, who are eager to provide their input to the budget after four years without any Senate budget plan.

In the House, life is so much easier to predict. Members meet at 10 a.m. for speeches, then at noon for legislative work.

Tuesday's four-hour debate on the GOP budget resolution means the House can move immediately to consider budget alternatives. Budget alternatives up on Wednesday are the Senate's budget plan, and budgets from the Congressional Black Caucus, the Progressive Caucus, the Republican Study Committee and the Democratic Caucus.

The House seems likely to debate a few of these and hold votes in the mid-afternoon, then debate the rest and vote on those in the early evening. Then, on Thursday, the House will pass the GOP budget, and also (we expect) the Senate-passed 2013 spending bill.

For those keeping score, these were the vote totals from last year in the House on budget alternatives that are reappearing this year:

Congressional Black Caucus — failed 107-314.

Progressive Caucus — failed 78-346.

Republican Study Committee — failed 136-285.

Democratic Caucus — failed 163-262.