1) ”Snowfall,” 10 p.m., FX; reruns at 11:05, 12:09, 1:13. Last week, the wedding party of Jerome and Louanne was spiked with LSD. It was a bizarre detour, but it led to revelations for Franklin (shown here in a previous episode) and Leon. Their stories continue this week, along with a fierce sub-plot: Louanne sent a crooked cop to kill a rival. Now opposite instincts are juggled: There might be peace and a crime-free life … or maybe retribution, with Los Angeles swarming with gang warfare. It’s a strong hour, leading to a huge – and crowded — season-finale next week.
2) “Nature: American Arctic,” 8 p.m., PBS. In the northeastern corner of Alaska, the Arctic National Wildlife Refuge offers goats, grizzlies, geese and more. Here is beautiful footage of contrasting lives: The expanding snow goose population has reached 20 million; the polar bear population has shrunk in half. Caribou – some 160,000 of them — make a 1,000-mile round trip each year; the 800-pound musk oxen stay stubbornly in place, poking through the snow.
3) “The Masked Singer” (Fox) and “Survivor (CBS), both 8 p.m. It’s a busy night for both reality shows. “Singer” will unmask two people, giving the show its second of three finalists. And “Survivor” has two hours; with 12 of its 18 contestants left, it has some of them switch tribes and also sends one to another island.
4) “The Wonder Years,” 8:30, ABC. This comedy-drama can be at its best when leaning to the drama side. Tonight, William is back from Vietnam; he has surprises – including an older girlfriend with an 8-year-old son – and some disturbing memories.
5) “Chicago Fire,” 9 p.m., NBC. Firefighting and crimefighting merge tonight. Chief Boden is held hostage in a grocery store; he tends to the wounded and tries to calm the hostage-taker … while wondering if there will be a rescue.