A political analyst updated his outlook for the House just days before midterm elections, giving the Democrats an even greater edge over Republicans hoping to maintain power.

Dave Wasserman, who is House editor of the nonpartisan Cook Political Report, tweeted Wednesday that their forecast was being updated, predicting that Democrats gain 30-40 seats, up from 25-35 seats.

Wasserman added that this prediction could change before the Nov. 6 midterm elections.



New: based on the past week’s evidence, we’re revising our House outlook to a Dem gain of 30-40 seats (was 25-35 last month) at @CookPolitical. This could change again before Tuesday. — Dave Wasserman (@Redistrict) October 31, 2018



The forecast suggests a so-called "blue wave" is becoming more likely. Democrats need to flip 23 seats to take control of the lower chamber.

In the Senate, which the GOP also controls, 24 Democrats and two independents who caucus with Democrats, are up for re-election. Nine Republicans are up for re-election. Only one seat, Sen. Heidi Heitkamp's, D-N.D., is rated anything below "toss-up" at "lean-R," according to Cook Political Report.

RealClearPolitics gives Democrats a smaller edge in the House than Cook, factoring in a number of toss ups. Their latest House elections map shows Democrats taking 203 seats versus 198 for Republicans. Thirty-four races are listed in the "toss ups" category.

Generic ballot polls also bode well for Democrats. RealClearPolitics' aggregate for the 2018 generic congressional vote gives a 7.5-percentage point advantage to Democrats. Also, one of the few polls that favored President Trump to win the 2016 election is now forecasting a strong general ballot for Democrats, showing them leading Republicans by 17 points.