It’s been a tough summer for new broadcast shows, and ABC’s ”Final Witness” did nothing to change that with its weak bow Wednesday. The night instead was led easily by NBC with a two-hour ”America’s Got Talent.”

According to preliminary national estimates from Nielsen, ”Final Witness” averaged a mere 1.0 rating/3 share in adults 18-49 and 4.2 million viewers overall in the 10 p.m. hour, placing fourth among the broadcasters in 18-49 and tying for third in adults 25-54 (1.4/4). A year ago, on the comparable night, the debut of ”Primetime Nightline: Beyond Belief” fared a bit better in demos 18-49 (1.2 rating in 18-49 and 1.6 in 25-54). The docudrama features dramatic re-enactments of grisly crimes and features the murder victims telling their stories.

ABC aired repeat comedies earlier on the night, starting with ”The Middle” (0.9/3 in 18-49, 3.7 million viewers overall) and ”Suburgatory” (0.8/3 in 18-49, 3.1 million viewers overall) and then ”Modern Family” at both 9 (1.3/4 in 18-49, 3.8 million viewers overall) and 9:30 (1.3/4 in 18-49, 3.7 million viewers overall).

NBC won the night, getting more solid numbers from U.S. Olympic swimming trials (1.9/7 in 18-49, 7.0 million viewers overall), followed by an expanded, two-hour installment of ”America’s Got Talent” (2.8/8 in 18-49, 10.5 million viewers overall), which was airing for a third straight night. Though it dominated its time period and was the night’s No. 1 show in just about every category, ”Talent” matched its summer low.

At Fox, ”So You Think You Can Dance” (2.0/7 in 18-49, 5.6 million viewers overall) was down from last week when it faced lesser competition, but matched its year-ago score. It won the 8 o’clock hour in adults 18-49 and finished second to NBC’s ”Talent” for the 9 o’clock hour; ”Dance” also ruled as Wednesday’s No. 1 show in women 18-34 (2.6/9).

CBS’ ”Dogs in the City” continued its struggles in the 8 o’clock hour (0.9/3 in 18-49, 4.7 million viewers overall), as the net fared better with encores of veteran dramas ”Criminal Minds” (1.4/4 in 18-49, 6.4 million viewers overall) and ”CSI” (1.1/3 in 18-49, 5.5 million viewers overall).

Univision ran third for the night in 18-49, led by ”La Que No Podia Amar” at 10 p.m. (1.6/6 in 18-49, 4.0 million viewers overall).

Preliminary 18-49 averages for the night: NBC, 2.5/8; Fox, 2.0/7; Univision, 1.3/4; CBS, 1.1/4; ABC, 1.1/3; CW, 0.3/1.

In total viewers: NBC, 9.3 million; Fox, 5.6 million; CBS, 5.5 million; ABC, 3.8 million; Univision, 3.5 million; CW, 0.7 million.