Donald Trump is Tuesday night's underdog. The Republican candidate needs 270 electoral votes to eke out a win over challenger Hillary Clinton.

Though his foe holds a lead of anywhere from one to 11 points, per the latest polls, a Trump presidency isn't a far-fetched thought in the final hours before Election Day. Real Clear Politics predicts Clinton/Kaine with 203 votes, Trump/Pence with 164, with 171 toss-up votes. It's a lot of ground for him to cover, but the scales could tip in Trump's favor. 

With no toss-ups, RCP sees Clinton winning battleground states Florida and Pennsylvania, with 29 and 20 electoral votes to offer, respectively. Trump would likely win Arizona's 11 votes, but Clinton's big win would tip the final scale 301 to 237.

Pennsylvania turned blue in 1992 and has stayed that way since. 

Florida has flipped between red and blue nearly every election since Clinton. In 2012, Barack Obama eked out a win over Romney by a margin of fewer than 75,000 votes; he won the state's 29 electoral college votes. 

Nate Silver's FiveThirtyEight sees the race for electoral college votes closer, predicting Clinton wins 293 and Trump getting 243. Its margin is even closer in the popular vote, at 48.6 percent versus 45.5 percent, favoring Clinton.

Still, one of the most popular forecasting sites sees Clinton victorious overall, betting the former secretary of state has a 65 percent chance of winning as of Monday. Per FiveThirtyEight's data, that figure has dropped significantly between the third presidential debate, when she had more than an 87 percent chance of winning. That's likely because of FBI Director James Comey's accusations against Clinton for criminal misconduct relative to her use of private email, and a more recent letter to Congress backpedaling from those statements.

Another popular forecasting tool, the New York Times' The Upshot, has more confidence in a Clinton presidency. According to their model, Trump has only a 16 percent chance of winning Tuesday. Over the last two weeks, Trump's gained ground, especially in Arizona and Florida, where his chances at winning those states has nearly doubled. But the billionaire candidate's odds of winning haven't been as high as they were after the Republican National Convention, when he had a 31 percent chance.

And in swing state Pennsylvania, The Upshot predicts Clinton has an 89 percent chance at winning its electoral votes.

Unlike FiveThirtyEight, The Upshot also predicts possible scenarios. Per the tool, Clinton has 693 ways to win, compared to Trump's 315. It all starts with winning Florida; depending on how the Sunshine State votes, the interactive map shows how each state must stack up to result in a GOP or Democratic win.

Next up, PredictWise sees an even narrower path for Trump, predicting a mere 11 percent chance at the Republican winning. His odds plummeted to just 9 percent late last month, after several women had come forth alleging sexual misconduct by the candidate, and his several comments against women in the third presidential debate. 

Clinton, meanwhile, saw a dip in chances earlier this month, again, likely from Comey's letter to Congress, but has since returned to the odds she held last month.

Clinton's high chance at winning seems contrary to popular opinion. Most polls show a margin of difference less than five points between the two candidates. But those are national polls, and this election will be hard-fought in the electoral college. 

That said, Clinton could win the way George Bush did. Or rather, Trump could lose like Al Gore. 

Chicago Tribune columnist Steve Chapman says its possible: Clinton could lose the popular vote and still take the oath of office. Citing an NPR study in 2012, Chapman said its possible to win the White House with only 23 percent of the popular vote.