NBC is basking in what appears to be its first November prime-time TV sweeps win in nine years, though the sweeps period doesn't officially end until Wednesday night and the numbers won't be official for another week.

Honchos at the perennially fourth-ranked broadcast TV network have followed the ratings with wide-eyed amazement, waiting for the bottom to fall out. But they have concluded over the last several days that it now appears too late for ABC, Fox, and CBS to catch them.

The last time NBC won a November sweeps was in 2003, when its prime-time schedule included the iconic shows Friends, ER, Frasier, and The West Wing.

A win would be a big feather in the cap of executive Steve Burke and Comcast Corp., the cable giant that said it would revive the bottom-dwelling NBC prime-time business when it acquired control of NBCUniversal in early 2011.

It would also come with one big asterisk, however: Just about everyone in Hollywood believes that when the snow flies in January and February, NBC's ratings are likely to sink like the mercury in Philadelphia because of the absence of NFL Sunday Night Football and The Voice, which will be off the air in the first months of 2013.

NBC Entertainment chairman Bob Green–blatt said in a phone interview that NBC appeared to be on the mend, but he cautioned against unrealistic expectations. A win would be a "bit of a gift," he said, and he's "cognizant of how fleeting it can be."

In February, CBS will televise the Super Bowl, a huge boost to viewership, and high-rated American Idol returns to Fox in early 2013.

Greenblatt and other studio officials attributed NBC's fall sweeps performance to Sunday Night Football, No. 1 in the 18- to 49-year-old demographic, with 10.5 million viewers, and surprisingly strong viewership for The Voice, Revolution, and Go On on Monday and Tuesday nights. Grimm, on Friday nights, has done well, too.

Also helping NBC have been weaker performances by Two and a Half Men on CBS, the consistently top-ranked network, and other shows on competing networks.

NBC barreled into the fall season after promoting its shows during the Olympics, then airing The Voice and Revolution one to two weeks before the official start of the fall season on Sept. 24, so the shows could build momentum.

November's sweeps period, which actually began Oct. 25, is one of three important sweeps in the broadcast-TV business (the others are in February and May), with ratings used to set local advertising rates.

Wednesday and Thursday nights remain problematic for NBC, but Greenblatt said the network hopes to improve with "small increments."

"I don't think CBS gives up its crown, but at least NBC is back in the game," said James Goss, media analyst with Barrington Research. "They have a couple of programs that have begun to click."

Contact Bob Fernandez at 215-854-5897 or bob.fernandez@phillynews.com or follow on Twitter @bobfernandez1.