(CNN) -- Illinois Sen. Barack Obama carries momentum from a sweep of weekend contests into this week's primaries in Maryland, the District of Columbia and Virginia.
Sen. Barack Obama greets supporters before a rally Sunday in Alexandria, Virginia.
New York Sen. Hillary Clinton, meanwhile, is coming off a campaign shake-up, while her advisers are seeking to lower expectations for this month's Democratic contests.
Obama came out ahead in Sunday's Democratic caucuses in Maine after wins in Saturday's Louisiana primary and Democratic caucuses in Nebraska, Washington and the U.S. Virgin Islands.
With 99 percent of precincts reporting in Maine, Obama was leading Clinton 59 percent to 40 percent. At stake are 24 delegates to August's Democratic national convention in Denver.
Those contests gave him a lead over Clinton in pledged delegates to the convention, but Clinton still held a narrow edge over Obama when "superdelegates" -- elected officials and party leaders -- are included in the tally, according to CNN estimates. Watch Obama talk about how he can beat John McCain »
After Saturday's results and a split decision in last week's Super Tuesday contests, Clinton shook up her campaign Sunday by replacing campaign manager Patti Solis Doyle with longtime adviser Maggie Williams, her campaign announced Sunday.
Clinton aides admit this month's remaining Democratic contests may favor Obama, but they plan to focus on a larger cache of delegates up for grabs in March.
"Although the next several states that hold nominating contests this month are more favorable to the Obama campaign, we will continue to compete in them and hope to secure as many delegates as we can before the race turns to Ohio, Texas and Pennsylvania," read a statement from Clinton's campaign.
Those states have high concentrations of voters who have been strong Clinton supporters -- Latinos in Texas and blue-collar workers in Ohio and Pennsylvania.
But Joe Trippi, an adviser to former Democratic contender John Edwards, said Sunday that Obama had "a full head of steam" after Saturday's wins and was poised to win the Potomac contests.
"It's hard to see a win for Sen. Clinton into March, into Ohio and Texas, which I think was what they're counting on," Trippi told CBS' "Face the Nation." "But even that's in jeopardy, I think, as Obama builds some momentum here."
On Tuesday, Clinton and Obama will be competing for 15 pledged delegates in Washington, D.C.; 70 in Maryland; and 83 in Virginia.
Both candidates tipped their hats to the state's Democratic brass on Saturday night by jetting into Richmond for the Virginia Democratic Party's annual Jefferson-Jackson fundraising dinner.
"We won north, we won south, we won in-between," Obama said. "And I believe that we can win in Virginia on Tuesday if you're ready to stand for change."
Clinton's remarks focused on the economic themes that have characterized her recent stump speeches.
"I am so ready to see Virginia in the winning Democratic column in November," Clinton told the audience.
Obama also beat two former Democratic presidents to win a Grammy award on Sunday night.
His recording of his book, "The Audacity of Hope: Thoughts on Reclaiming the American Dream," took the recording academy's award for best spoken word album -- topping former presidents Bill Clinton and Jimmy Carter. E-mail to a friend