Here come the Leonids Attention, skywatchers. That annual fall light show, the Leonid meteor shower, returns the night of Nov. 17, and some astronomers have suggested that this year's event could be quite a spectacle. The shower takes place every November, when Earth passes through a stream of debris shed by Comet 55P/Tempel-Tuttle. Every 33 years or so, when the comet passes close by, Earth encounters an especially dense part of the debris stream. Observers then see a heavy shower or even a storm, when more than 1,000 meteors streak across the sky in less than an hour. Earth last witnessed a Leonid storm in 1966. A team of British and Australian astronomers has predicted a moderately good show for this year and next-stronger than in 1998-but they say the real McCoy won't occur until 2001 and 2002. Other astronomers doubt such forecasts. Although Europe and Africa may have ringside seats this year, North America, especially the East Coast, could also witness some fireworks. Start gazing eastward around midnight, when the constellation Leo rises. Viewing might improve after the moon sets, but activity may have dwindled by then.