Democratic presidential nominee Sen. Barack Obama appears to be enjoying a bounce in national polls after the Democratic National Convention.

Rasmussen Reports said Obama attracted 48 percent of the vote while Sen. John McCain earns 43 percent in its daily tracking poll released Tuesday. When "leaners" are included in the findings, Obama has 51 percent and McCain has 45 percent.

CBS News said that in its latest poll, Obama’s lead over McCain has grown to 48 percent to 40 percent. The eight-point lead is up from Obama’s three-point lead before the convention.

The latest USA Today/Gallup poll gives Obama a 50-43 percent lead among registered voters. McCain's advantage in handling terrorism was dramatically reduced, and his "unfavorable" rating ticked up, the poll said.

Post-convention poll bumps are common; it remains to be seen whether McCain enjoys improved numbers. Hurricane Gustav prompted President George W. Bush and Vice President Dick Cheney to cancel their planned Monday speeches. And McCain ordered conventioneers to tone down the political rhetoric as the storm blew ashore over New Orleans on Monday.

Disclosures about McCain's vice presidential running mate, Gov. Sarah Palin of Alaska, were extra diversions on the truncated first day of the convention, drawing the glare of reporters and throwing the candidate's campaign off its script.

The announcement that Palin's unmarried daughter, 17, is five months pregnant, and that an attorney has been retained to represent the governor in a probe of her firing of the Alaska public safety commissioner, took away from a convention that had been carefully managed to reintroduce McCain to an anticipated massive television audience.

Obama became the first black American nominated by a major U.S. political party to run for the presidency last Thursday, accepting the challenge in front of tens of thousands of chanting, flag-waving supporters packed in to a Denver football stadium.

Nielsen Media Research said 38 million TV viewers saw Obama's speech -- more than watched the Olympics opening ceremony in Beijing, the final "American Idol" or the Academy Awards this year.