Alan Abramowitz takes an early look at the midterm elections. Using the most recent generic ballot numbers (shown above), his model predicts that the Democrats will pick up one House seat:
The results of the midterm forecasting model indicate that while Democrats have a real chance to buck the normal pattern of midterm elections and gain seats in the House of Representatives, they are unlikely to pick up the 17 seats that they would need to regain control of the chamber. That outcome would require a wave election like 2006 or 2010. But the 2014 midterm election is unlikely to be a wave election. It is much more likely to be a status quo election for the House of Representatives with one party or the other making a small gain and Republicans holding onto their majority.
More from Abramowitz here.