PHILADELPHIA Ernest Stuart - trombonist, entrepreneur, and organizer of the Center City Jazz Festival - stopped as he darted up the stairs at Fergie's Pub Saturday to check on one of the acts.

The day so far had been a blur of activity. The events had sold out, the clubs were packed, and simply keeping up had become a challenge. Mayor Nutter was grabbing a late lunch at Time as jazz trumpeter Charles Washington played to an overflow crowd, and he was sending Stuart encouraging texts.

"There is just so much going on," Stuart said as he scrolled through the text messages on his iPhone.

The festival, in its third year, unfolded with hundreds of jazz lovers ping-ponging from one club to another during the afternoon and early evening, an unaccustomed time for jazz but one the organizers say draws an eclectic mix of young music fans looking to start the party early and older aficionados who want to wrap things up at a rational hour.

The performances, tightly scheduled to encourage listeners to move from one club to the next, took place at Time, Chris' Jazz Cafe, Fergie's, and MilkBoy Philadelphia, all within a few blocks of one another.

In one sense, it was a jazz-lover's ideal - a handful of clubs, each with its own musical offering, all within easy reach (and on a sunny afternoon, no less). But it was easy to see that the festival could become a victim of its own success. In most places, there was standing-room only, and now and then the clubs were so packed people simply turned around and left.

"I just wish it were more roomy" Chantel Green said outside Fergie's, where she had gone to listen to jazz vocalist Rhenda Fearrington.

Dan Monaghan, a drummer who teaches jazz at Temple University and plays with Philadelphia vocalist Joanna Pascale - she performed for a packed house at Time - said he was glad the city had its own jazz festival because so many of the nation's jazz greats traced their roots here.

"I am thrilled," said Monaghan, an artist in residence at Temple. "It's a long time coming."

Stuart estimated ticket sales, which were ended Saturday morning because of the demand and the limited capacity of the clubs, would reach 750, a jump from last year, when about 500 attended.

Next year, he said, he may have to look for more space.

Once inside the clubs, listeners were served a smorgasbord of acts that ranged from the cool jazz style of early Miles Davis to the more avant-garde. At Time, trumpeter Charles Washington's cerebral musical style was met with spontaneous applause throughout his hour-long performance.

Nutter said the event, and the public response to it, was reflective of the city's rebound, so much so that his administration had begun discussions about the possibility of planning a major jazz festival that would draw musicians and fans from around the country.

"It is great," Nutter said. "It brings a liveliness to the city."

At MilkBoy, as vocalist Peter Gaudioso offered up his own engaging take on the Great American Songbook classic "Time After Time," Maryanne Parlato of South Philadelphia looked on appreciatively.

Parlato, who went with Gaudioso's mother, Carla Aldi, said she tended more toward rock, or even opera, and wasn't necessarily a jazz fan. But she was sold on Gaudioso's performance and the festival.

"What a great idea," she said.