How to watch midterm elections unfold tonight, hour by hour

President Donald Trump isn't on today's ballots, but the results will inevitably be interpreted as voters' verdicts on him and his policies.

All 435 seats in the U.S. House of Representatives will be decided, and that's where a Democratic "blue wave" could materialize. Republicans hope to retain or increase their slight advantage in the U.S. Senate in 35 contests. The 36 governors who will be chosen may play key roles in redistricting after the 2020 census.

Here's a guide to watching the returns.

4 p.m. Mood inklings: The first exit polls – interviews with voters after they cast ballots – will be released. They're a guide to voters' moods and the issues that are on their minds and influence what TV talking heads say about how things are going. It's a mistake, though, to assume they say anything about who's winning. Exit polls incorrectly predicted a presidential win for Democrat John Kerry in 2004.

6 p.m. First hints: Virginia polls close. Republican U.S. Rep. Dave Brat's fate could presage how other Trump allies and women challengers will fare. Democrat Abigail Spanberger outraised Brat; late polling had the Seventh District race deadlocked.

6:30 p.m. Blue wave gauge: North Carolina polls close. It would be an ominous sign for other Republicans if Mark Harris, a Baptist minister, doesn't prevail in the fight for the Ninth Congressional District open seat. Democrat Dan McCready is making a play for moderate voters by pledging not to back liberal lightning rod Nancy Pelosi as speaker if Democrats take over.

7 p.m. 2020 preview: Voting ends in Florida's Central Time Zone counties. In the nation's most costly U.S. Senate race, Democratic Sen. Bill Nelson is trying to fend off outgoing GOP Gov. Rick Scott. The outcome will shape 2020 expectations: Trump won here by 1 percentage point and the state has voted for presidential winners since 1996.

7 p.m. Making history: Polls close in most of Michigan, where Democrat Rashida Tlaib, who has no Republican opponent, is all but certain to win in the 13th District, making her the first Muslim woman elected to the U.S. House. In another hour or so, Minnesota's Ilhan Omar, a Fifth District Democrat, could join her.

8 p.m. Minnesota polls close: As of Monday, nearly 540,000 Minnesotans had cast early votes. And anyone already on line as of 8 p.m. has the right to cast their ballot.

8 p.m. Socialist yardstick: Polls close in New York. If Alexandria Ocasio-Cortez wins the 14th District seat in the U.S. House, she'd be — at 29 — the youngest member of Congress. A victory also could generate a slew of other democratic socialist candidates inspired by Sen. Bernie Sanders.

8 p.m. What happens with Walker? Polls close in Wisconsin. Republican Gov. Scott Walker struggled to build a lead over Democrat Tony Evers. If he loses, will it be because Wisconsin voters are tired of the incumbent — or tired of Trump, whom he enthusiastically supports? The state was crucial for Trump, and Democrats want it back in 2020.

9 p.m. Starting line: Polls close in Iowa. The 2020 presidential campaign has already begun with visits from multiple Democratic prospects, including Minnesota Sen. Amy Klobuchar. They'd all like Democrat Fred Hubbell to beat GOP Gov. Kim Reynolds.

9 p.m. More tea leaves: Utah's polls close. U.S. Rep. Mia Love — the first black Republican woman elected to Congress — is in a tight race in the Fourth District against Salt Lake County Mayor Ben McAdams, a Democrat. If Trump were on the ballot in this red state, he'd be hurting: An October poll put his approval rating at 45 percent, down from 58 in 2017.

10 p.m. Kavanaugh fallout: Polls close in southwest North Dakota. Sen. Heidi Heitkamp, a Democrat who voted against Brett Kavanaugh's U.S. Supreme Court nomination, did so knowing that it might end her political career. If she loses to Republican Kevin Cramer and GOP candidates hold on elsewhere, the party could improve its 51-49 Senate edge.

Midnight Overtime: Last Alaska polls close. There will be a Nov. 27 runoff in Mississippi if nobody gets more than 50 percent in the U.S. Senate contest. If a gubernatorial candidate doesn't get more than half Georgia's votes, two top finishers will meet Dec. 4.

-- Judy Keen