Another poll from Quinnipiac University shows Democrat Bill de Blasio leading the mayoral primary field handily — in Democrat-heavy New York City. There are caveats, but the poll reinforces a trend that emerged with the implosion of Anthony Weiner.

First, the updated results. We've included both Quinnipiac and non-Quinnipiac polling, but the trend is clear.

There's a caveat worth noting, as pointed out by The New York Times' Mike Barbaro: this poll includes "leaners," meaning that if a respondent is thinking about voting for de Blasio, that voter is included in de Blasio's total. But de Blasio's support isn't much softer than that of his two main opponents, City Council Speaker Christine Quinn and former comptroller Bill Thompson. Each sees about the same level of support — meaning that things could shift dramatically, but there's no reason to think that de Blasio's leaners are any more likely to bail on him than, say, Quinn's.

The poll reinforces one possible explanation for de Blasio's surge. Quinn, who positioned herself as an ally to the current mayor, Mike Bloomberg, before term limits were extended in 2009, is seen by many as the candidate who will continue the current mayor's practices. It was only over the weekend that Quinn formally opposed the controversial practice of stop-and-frisk, which was recently ruled to have violated the Constitution. Until Weiner's 2012 online escapades came to light, he was the protest vote against Bloomberg. When he collapsed in August, de Blasio and Thompson surged. Quinnipiac asked voters if there was any candidate that they would not vote for. Forty-four percent of respondents said they would never vote for Weiner. Thirty-five percent said Quinn.

So why has de Blasio kept moving up while Thompson has faded? In part because de Blasio's fortunes with black voters have improved. In the first poll showing him ahead, a month ago, Thompson got 39 percent of the black vote to de Blasio's 22 percent. Now, the figures have flipped. Black voters prefer de Blasio 47 percent to Thompson's 25. The extent to which that may be due to de Blasio's heavy-rotation TV ads featuring his African-American family — ads that have made his afro-sporting son famous — isn't much of a mystery. 

None of this is set in stone. Another poll, conducted by NewsDay, indicated that de Blasio still trails with black voters. And things change if de Blasio doesn't hit the 40 percent mark in the September 10th primary. If that happens, he faces a run-off. That probably doesn't worry him much: voters prefer him to Quinn, still a likely second-place contestant, by a more than two-to-one margin. If he progresses to the general election, de Blasio would likely face former transit chief Joe Lhota. And win, easily — at least if a June poll showing de Blasio up 52 to 15 is any indicator.

Duh BLAH-zee-oh. Learn that pronunciation. It may come in handy.

Photo: The candidate and his family at the West Indian Day Parade. (AP)