WORTH NOTING ON TV

* SATURDAY

Carreras, Domingo, Pavarotti With Mehta: The Three Tenors in Concert 1994 (PBS, 11 p.m-1:30 a.m., EDT): OK, so it isn't going to take place at the Baths of Caracalla in Rome, where the big three first sang together in 1990, but at Dodger Stadium in Los Angeles. By the time the singers get to the new setting, however, it will have been converted, by 600 craftsmen from three continents, into a neoclassical set framed by 20 big columns, with two waterfalls and lots of greenery.

Even the broadcast's daunting 2-1/2-hour running time is impressive, and it is expected to be seen by a world TV audience of up to 1 billion, and by a stadium audience of some 56,000.

The main point, of course, is that the show boasts the world's three best-known tenors: Jose Carreras, Placido Domingo, and Luciano Pavarotti, with Zubin Mehta conducting the Los Angeles Philharmonic Orchestra and the Los Angeles Music Center Opera Chorus. This is the first time the three singers have performed with Mehta in the United States, although their ``act'' was launched in Rome on the eve of the 1990 World Cup finals, in a broadcast repeated endlessly on some public stations during pledge periods.

This new event is taking place on the eve of the 1994 World Cup soccer finals, and the real evidence of its big-time status is this: It will be blacked out in the Los Angeles area.

Mixed in with operatic arias and other serious fare are selections on the light side, like a ``Tribute to Hollywood'' and a medley of favorite tunes called ``Around the World'' in tribute to the World Cup.

(Preceding the concert, from 10:30 to 11 p.m., a live preview offers conversations with the four artists and other features.) * SUNDAY

World Cup final (ABC, 3:30 -6 p.m., EDT): Brazil faces Italy in live coverage from the Rose Bowl in Pasadena, Calif. Roger Twibell, Seamus Malin, and Rick Davis are the sportscasters.

Please check local listings for these programs.