I thought the conventional wisdom was the opposite, no? That the House, even as gerrymandered as it is, is super vulnerable to the president's popularity, but the senate has a very favorable GOP map this year. I think there are like 10 dems up for reelection in Trump states, or something crazy, but only a couple republicans in Clinton states.
The president loses 10-20 house seats in midterms in a year when he's popular. Could be a bloodbath. Both houses should be in jeopardy given that the approval rating could be in the 20s by next fall. Already breaking records.