There have been several polls released recently, showing everything from a virtual dead heat to Elizabeth Warren ahead by low single digits.

This was a contrast to pre-DNC polls, which showed Brown ahead by low single digits.  Clearly Warren received a convention bounce, almost entirely from increased support from Democrats.

Warren supporters in the left-blogosphere have all but declared victory.  The question, however, was whether Warren’s convention bounce would last.

A U.Mass-Lowell/Boston Herald poll released tonight indicates that perhaps Warren’s lead is not so clear, or that her bounce has faded.  Brown is up 50-44 among registered voters and 49-45 among likely voters:

U.S. Sen. Scott Brown has moved into a narrow lead over rival Elizabeth Warren while his standing among Massachusetts voters has improved despite a year-long Democratic assault, a new UMass Lowell/Boston Herald poll shows.

The GOP incumbent is beating Warren by a 50-44 percent margin among registered Bay State voters, a turnaround from the last UMass Lowell/Herald poll nine months ago that had the Democratic challenger leading by seven points. Among likely voters, Brown is leading the Harvard Law professor by a 49-45 percent margin, just within the poll’s 5.3 percent margin of error.

“I wasn’t too sure of him at first but he’s been very independent,” said Jo Ann Dunnigan, a longtime Democrat and President Obama supporter from Fall River who participated in the poll, conducted Sept. 13-17….

The poll, conducted by Princeton Survey Research Associates, shows nearly one in three Brown backers say they could change their mind before Election Day, compared to just 19 percent for Warren. But the poll, which started a week after the Democratic National Convention, finds no evidence of a “bounce” for Warren.

There also is some troubling news for the well-financed Warren campaign. Despite spending millions of dollars to tarnish Brown’s image, the GOP incumbent’s popularity has actually increased in the last nine months….

The poll also shows Brown continuing to hold a huge lead among self-described independent voters, 58 to 35 percent. He has also pulled even on an issue Warren has sought to make her own — fighting for the middle class. Asked which candidate would look out for the interests of the middle class, 46 percent of registered voters said Warren and 44 percent said Brown.

Self-described Democrats accounted for 28 percent of the poll respondents, and Democratic-leaning voters made up 55 percent of the poll.

[I note that PPP which showed Warren ahead by 2 had a higher percentage of self-identified Democrats, 38%.  According to the latest data, 35% of voters are registered Dems, but over half unaffiliated, with the electorate trending unaffiliated.]

Brown is a very likable guy who appeals on his own merits to voters.

I remain convinced that when the glow of the DNC bounce fades, so too will Warren’s campaign.

Her rise is a result of money and party affiliation, not because she appeals on her own merits to voters.  It will be hard for her to maintain that charade for several more weeks.