NBC continues its sweeps roll, taking huge leads at the month’s halfway point after a big victory on Wednesday night. It’s also shaping up to be a great month for the WB, which joins the Peacock as the biggest year-to-year gainers.

After solid performances on Wednesday, NBC and the WB are both up 13% year-to-year in adults 18-49. UPN, up 6%, is the only other net to improve.

According to Nielsen, NBC won Wednesday by 6 shares over ABC and Fox in adults 18-49 and by about 6 million viewers over CBS in total audience. Net again captured the night’s five final half-hours in the key demo, led by “Law & Order” (7.5/20) and “The West Wing” (6.3/16).

The strong showing has helped NBC expand its sweep leads in all key measures: adults 18-49, 25-54, 18-34 and total viewers. NBC has won 10 of the first 14 nights in adults 18-49; CBS and Fox have each taken two (including one tie); and ABC, one.

Surviving ‘Buffy’ loss

The WB followed its impressive Tuesday showing with a strong “Dawson’s Creek,” which won its hour in women 18-34 with its best score in a year (5.1/15) and tied ABC’s comedies for the adults 18-34 lead (3.5/11). Combined with “Felicity,” the Frog won its 8 to 10 p.m. block in women 18-34.

Despite losing its No. 3-rated show of a year ago, “Buffy the Vampire Slayer,” the WB has maintained or improved in all key measurements vs. last May.

Elsewhere, CBS is running second in adults 18-49, 25-54 and total viewers — with some of its biggest nights still ahead. Net finished second Wednesday in adults 25-54 and total viewers, led by the penultimate episode of “The Amazing Race,” whose 4.2/10 in adults 18-49 was a solid second to “West Wing” at 9.

ABC again won Wednesday’s opening hour in adults 18-49 (3.7/11) behind the laffer combo of “My Wife and Kids” and “According to Jim.” Fox, tied with ABC for second in 18-49 on the night, was led by “Bernie Mac” at 9 (4.0/10).

ABC and Fox figure to be in a competitive battle for third place for the month in 18-49.

UPN finished second Wednesday in men 18-49 behind two episodes of “Enterprise,” whose 8 o’clock seg delivered the series’ best scores (5.34m, 2.9/8) since November. Net is up 13% year-to-year in adults 18-34.