Following the conclusion of the Democratic Convention in late July, it was hard to imagine a tight race to the White House, as Democratic nominee Hillary Clinton was far outpacing Republican Donald Trump. But with 40 days remaining until Election Day, no candidate has a clear advantage in capturing the 270 electoral college votes due to tight races in key swing states.

By most accounts, Clinton won the important first presidential debate Monday night. Post-debate scientific surveys from outlets like CNN/ORC and Public Policy Polling confirmed that Clinton finished with a clear edge and data-driven website FiveThirtyEight predicted her debate effort would likely result in some sort of boost in the polls. The first post-debate national poll from Morning Consult had Clinton leading 45 percent to 41 percent in a head-to-head matchup, after trailing Trump on Sunday, 39 percent to 38 percent.

But as the candidates return to the campaign trail, some of the recent data from crucial battleground states has been less promising for Clinton. For instance, a focus group conducted by the Charlotte Observer and McClatchy of 21 North Carolina voters found that four of those who were undecided actually moved away from the Democratic nominee after the debate. Though the small sample size must be taken with a grain of salt, the Democratic nominee could use a boost in North Carolina, which currently has a 58.3 percent chance of going to Trump, according to the FiveThirtyEight polls-only election forecast. The Real Clear Politics average of polls has the Republican nominee up by less than one point. President Obama captured North Carolina's 15 electoral votes, but lost the state in 2012.

Pennsylvania, worth 20 electoral votes, could also prove pivotal to swinging the election. The race in the Keystone State has drastically tightened over the past few months. Clinton has a 66.1 percent chance of winning Pennsylvania, according to the polls-only forecast, but it's gotten tighter. The Real Clear Politics average of polls has Clinton leading Trump 43.6 percent to 41.8 percent in a four-way race featuring Libertarian nominee Gary Johnson and Green Party nominee Jill Stein. The latest survey, from CNN/ORC, had Clinton leading Trump, 45 percent to 44 percent, in a four-way race.

Florida, which infamously decided the 2000 election, is another highly coveted state. The latest poll from Suffolk University before the debate showed Trump leading in a six-way race, 45 percent to 43.6 percent, while a Monmouth University survey had Clinton up by five points. She leads by just half of a percentage point in a four-way race, according to the Real Clear Politics average. The polls-only FiveThirtyEight forecast, however, gave Trump a 55.8 percent chance of winning the state Wednesday. Worth a massive 29 electoral votes, Florida has the highest probability of tipping the election at 16.7 percent, according to FiveThirtyEight.

Ohio, meanwhile, has steadily faded toward Trump. President Obama won the state in 2008 and 2012 in relatively close votes. The last five polls included in the Real Clear Politics average have all found Trump leading, by as much as five percentage points and as little as one point. Trump now has a 62.3 percent chance to take Ohio's 18 electoral votes, the polls-only forecast found Wednesday.

Ohio's neighbor, Michigan, appears to be leaning towards Clinton. The most recent Detroit Free Press poll had Clinton leading Trump in a four-way race 38 percent to 35 percent. The Democratic nominee has a 67.7 percent chance of taking Michigan, FiveThirtyEight predicted.

FiveThirtyEight found the general election overall is effectively a toss-up. Clinton apparently has about a 55.8 percent chance of winning, while Trump has a 44.2 percent chance.