When L.A. Law began its fifth season last fall, sagging ratings suggested the series was running out of energy. But this spring, the drama came roaring back with plot twists, surprises, cliff-hangers-and some of its best ratings ever. On May 16, Law's season finale came in third for the week, the highest ranking in its history. Elsewhere on NBC's schedule, a new drama is establishing a foothold. In just two airings, Sisters did well enough to earn a spot in the fall lineup. NBC is expected to win the May challenge from CBS, which won the week ending May 19 thanks to top-15 showings for ''Crocodile'' Dundee II and the Miss Universe pageant. ABC will finish a weak third, and the once-surging Fox network is licking its wounds from a May bomb; its heavily hyped movie Robin Hood aired May 13 and ranked 76th. LAST VIEWERS* TOP TEN WEEK 1 26.9 MOVIE: KNIGHT RIDER 2000 - NBC, Sunday, 9 p.m. 2 25.0 AMERICA'S FUNNIEST PEOPLE 4 ABC, Sunday, 8:30 p.m. 3 23.3 L.A. LAW 8 NBC, Thursday, 10 p.m. 4 22.5 AMERICA'S FUNNIEST HOME VIDEOS 6 ABC, Sunday, 8 p.m. 22.5 60 MINUTES 22 CBS, Sunday, 7 p.m. 6 22.4 DINOSAURS 7 ABC, Friday, 8:30 p.m. 22.4 MURPHY BROWN 13 CBS, Monday, 9 p.m. 8 21.9 ROSEANNE 2 ABC, Tuesday, 9 p.m. 9 21.8 CHEERS 3 NBC, Thursday, 9 p.m. 10 21.7 DESIGNING WOMEN 11 CBS, Monday, 9:30 p.m.
BOTTOM FIVE 83 6.3 TOTALLY HIDDEN VIDEO 84 Fox, Saturday, 8:30 p.m. 84 6.1 AMERICA'S MOST WANTED 79 Fox, Friday, 8 p.m. 6.1 TRUE COLORS 83 Fox, Sunday, 7 p.m. 86 6.0 THE WORLD'S GREATEST STUNTS 3 - Fox, Friday, 9 p.m. 87 4.0 TOTALLY HIDDEN VIDEO 84 Fox, Saturday, 8 p.m. *IN millions week of May 13-19
