The latest polling averages, according to Real Clear Politics, point to a seven-seat pickup for Republicans in the Senate, which would give them a 52-48 majority. Here's a quick rundown of the latest forecasts and predictions:
FiveThirtyEight's Nate Silver gives Republicans a 76.2% chance of winning a Senate majority. The most likely outcome (22.7%), according to his model, is Republicans flipping eight seats for a 53-47 majority.
The New York Times' model has Republicans' chances of flipping the Senate at 70%. The model gives Republicans a better than 60% chance in Alaska, Iowa, Colorado, and Louisiana.
The Washington Post's model has Republicans' takeover as a virtual certainty - 98%. It also forecasts an eight-seat GOP flip for a 53-47 majority.
The Huffington Post's model gives Republicans a 79% chance. The model's most likely outcome, at 22%, is a 52-48 GOP majority.
Princeton University professor Sam Wang, whose model has been the most bullish for Democrats, has the most likely outcome as a 52-48 Republican majority.
The University of Virginia's Larry Sabato projects Republicans will gain a 53-47 margin - by holding their three competitive races and flipping Louisiana, Arkansas, Alaska, South Dakota, West Virginia, Iowa, Colorado, and Montana. Sabato's Crystal Ball team also projects Republicans will pick up nine seats in the House, giving them a 243-192 majority.
Here's a look at the averages of polls in key states, according to Real Clear Politics:
New Hampshire: Sen. Jeanne Shaheen (D) leads Scott Brown (R) by 0.8
Iowa: Joni Ernst (R) leads Bruce Braley (D) by 2.3 points
Kansas: Greg Orman (I) leads Sen. Pat Roberts (R) by 0.8 points
North Carolina: Sen. Kay Hagan (D) leads Thom Tillis (R) by 0.7 points
Georgia: David Perdue (R) leads Michelle Nunn (D) by 3.0 points
Alaska: Dan Sullivan (R) leads Sen. Mark Begich (D) by 2.4 points
Arkansas: Tom Cotton (R) leads Sen. Mark Pryor (D) by 7.0 points
Colorado: Cory Gardner (R) leads Sen. Mark Udall by 2.5 points
There's still one factor that could complicate Republicans' plans to celebrate Tuesday night. FiveThirtyEight's Harry Enten recently projected there's a 47% chance the midterm elections will "go to overtime."
The two biggest potential factors for an election extension are increasingly likely runoffs in Louisiana and Georgia, if no candidate gets more than 50% of the vote Tuesday night.