The GOP is poised to make substantial gains in the Senate but control is still up in the air. Usually when the House turns to the minority party the Senate does as well (1946, 1954, 1994, 2006) but this year may be an exception. It is very easy to see a scenario where the Republicans control the House (this is almost a certainty) and the Democrats still have control of the Senate.
Unless there's a serious hiccup here's the six seats the GOP will certainly pick up in the Senate:
Here are the four seats that are true tossups:
Here are the three seats that still leans Dem:
I'm assuming that Florida, Kentucky, New Hampshire, Missouri and Ohio and Alaska all stay in the GOP column. As you can see, the GOP would need to pick of four of the seven seats in the "tossup" or "lean Dem" group to take control. What's even more interesting is that Illinois, West Virginia and New York are all seats that can be claimed immediately in November because they are "vacancy" seats appointed by their respective governors after they were vacated by their Democratic officeholder. If the GOP were to win these they would have between 42-44 for the "rump" session of the Congress that will meet after the November elections.
Tomorrow I'll tackle the complex and chaotic situation in New York.