A former chairman of the National Republican Congressional Committee said Thursday that he is seeing a “momentum shift” away from Democrats ahead of the November 2010 elections but cautioned against making predictions of significant Republican gains more than a year before the balloting.

Former Virginia Rep. Thomas M. Davis III, who served in the House from 1995 through 2008 and now is president of the centrist Republican Main Street Partnership, told reporters that the first midterm election in a new presidential administration has almost always yielded seat gains in Congress to the party not controlling the White House.

Though Republicans still have poor approval ratings, they could make gains in a low-turnout 2010 election from voters who are uneasy with one-party rule in Washington. Democrats have advantages of 256-178 in the House and 59-40 in the Senate.