Why is “Lost” (8 p.m., ABC) a hit? Is it the show’s impressive production values? The pilot is said to have cost more than $16 million. Are “Party of Five” fans rallying to Matthew Fox’s next big thing? Are “Survivor” faithful, bored by the show’s current torpor, turning to this scripted tale of castaways stranded on a desert isle?

“Lost” has more going for it than solid drama and better-than-average character development. At the risk of sounding pretentious, this show may just be most adept at reflecting the current national zeitgeist. Every once in awhile, shows come along that capture the feeling of their time. It’s impossible to watch an old episode of “The Twilight Zone” and not sense the fear of atmospheric H-bomb testing, backyard bomb shelters and “we will bury you” rhetoric between testy superpowers. If “The X-Files” preached that “the truth is out there,” “Lost” makes it clear that the beast is out there, ready to strike at any time, without reason or warning. It’s not a pleasant sensation, but I can’t help but feel that we’re all a little “Lost” right now.

Tonight’s highlights:

• The weather disaster miniseries “Category 6: Day of Destruction” (7 p.m., CBS) concludes.
• A violent, gun-wielding Santa stalks the arrival gates on “LAX” (7 p.m., NBC).
• Josh has a fateful crack-up on “The West Wing” (8 p.m., NBC).
• Brutality in Chinatown on “CSI: NY” (9 p.m., CBS).
• A shock jock given to pranks claims to have been shot on “Law & Order” (9 p.m., NBC).

Series notes

Hyde’s sister has an attitude problem “That ’70s Show” (7 p.m., Fox) … Catwalk catastrophes on “America’s Next Top Model” (7 p.m., UPN) … Jane Seymour guest stars on “Smallville” (7 p.m., WB).

Stiff upper lips on “Nanny 911” (8 p.m., Fox) … Life’s too short to watch “The Bachelor” (8 p.m., ABC) … Cheerleader litigants on “Kevin Hill” (8 p.m., UPN) … A hausfrau and a working mother trade families on “Wife Swap” (9 p.m., ABC).

Late night

Renee Zellweger and Chris Raxworthy appear on “Late Show with David Letterman” (10:35 p.m., CBS) … Jay Leno hosts Colin Farrell and Fantasia Barrino on “The Tonight Show” (10:35 p.m., NBC).