WASHINGTON — The Democrats are likely to lose 47 seats and control of the House of Representatives in November's elections, a top political analyst says in a new forecast Thursday.

Larry Sabato, a political scientist at the University of Virginia, also says that the Democrats are likely to lose eight or nine seats in the Senate, eight governors' offices and 300 to 500 seats in state legislatures.

"The numbers are eye-catching. Republicans are dramatically gaining in all categories," Sabato said in an interview. "It's generated by a rotten economy and a strong conservative reaction against President (Barack) Obama."

The analysis marks the first time this year that Sabato and the University's Center for Politics have predicted a Republican takeover of the House.

Sabato is one of the most consistently accurate election prognosticators. His final pre-election analysis in 2006 got the exact number of Democratic gains in the House and Senate and was off by only one in governors' races. In 2008, he missed the final Electoral College count by only one, and missed the final House tally by only five seats.

"2010 was always going to be a Republican year, in the midterm tradition. It has simply been a matter of degree," Sabato said in a written analysis released Thursday.

"Had Democratic hopes on economic revitalization materialized, it is easy to see how the party could have used its superior financial resources, combined with the tendency of Republicans in some districts and states to nominate ideological fringe candidates, to keep losses to the low 30s in the House and a handful in the Senate."

With Labor Day looming, Sabato wrote, it's now clear that the summer didn't turn out as Democrats wanted.

"Conditions have deteriorated badly for Democrats over the summer. The economy appears rotten, with little chance of a substantial comeback by November 2nd.

"Unemployment is very high, income growth sluggish and public confidence quite low. The Democrats' self-proclaimed 'Recovery Summer' has become a term of derision, and to most voters — fair or not — it seems that President Obama has over-promised and under-delivered."

Across the board, Sabato forecasts larger Democratic losses than he projected in the spring, when he and his Center for Politics predicted that the Democrats could lose 32 House seats. That would be a large setback, but Republicans must gain 39 seats to take control of the House.

Democrats now control the House by 255-178, with two vacancies, one previously held by each major party.

A switch of 47 seats would put the Republicans in charge by at least 226-209, assuming the two vacant seats remain in the same partisan control. Rep. John Boehner, R-Ohio, is in line to be the new speaker of the House. His party would chair all House committees, and would gain subpoena power to force the Obama administration to answer questions.

At least one other nonpartisan analyst also is now predicting a Republican takeover of the House. University of Buffalo political scientist James Campbell forecasts that the Democrats will lose 51 or 52 seats.

Sabato's new forecast also envisions larger losses in the Senate: eight or nine, up from the seven seats he previously predicted. Republicans must gain 10 Senate seats to take control there, however.