As voters prepare to cast their ballots in pivotal midterm elections in 18 days, split control of Congress appears to be the most likely outcome.

In the past week, Democratic House candidates have unveiled massive fundraising numbers that could give them more momentum toward seizing the chamber on Nov. 6, according to top forecasters. The battle for the Senate could not look more different. Prognosticators believe Republicans have a strong grasp on the chamber despite the House trends.

Democrats have to flip a net 23 GOP-held House district to take a majority, and nonpartisan experts think the target is well within the party's reach. Winning the two net seats needed to flip the Senate while facing a brutal map is much more difficult for the party.