What are the bellwether elections in the midterms (2018)?

So as I sit down and watch election returns coming in on November 6th, what are some of the early returns that will indicate that

  1. The Dems will pick up seats in the Senate, ready to retake it in 2020 and are going to retake the House “All Hail Skeletor Pelosi!” Hillary says, “I’ve got this.” and dusts off her campaign notes.
  2. MAGA!!! All that reporting about the Dems getting support was Fake News ™!! The Pubs start chanting 4 more years getting ready for 2020. Trump is so elated he talks about how this Congress will make the Chinese pay for The Wall ™ and grabs Angela Merkel’s pussy yelling “This is what we’ll do to our Trade Enemies ™”.

I’m thinking they need to be Congressional Elections (House and Senate) and early on (Eastern or Central time zone) but feel free to put up any election you feel shows how the 2018 midterms will go.

Any election can be a bellweather, if you look beyond just the Boolean win/lose. If a Democrat is expected to win by 10 but wins by 15 instead, that’s good news for the Democrats. If, by contrast, they win by only 5, that’s good news for the Republicans. Of course, the best data would come from aggregating many such races in this way, with weighting for margins of error.