As Winter Storm Fern barrels in, all eyes are on the Weather Channel. Its CEO is charting the company’s next big forecast: growth

With roughly 150 million Americans in the crosshairs of a massive winter storm that will bring ice, snow, or both from New Mexico to Maine and 32 other states in between, all eyes are on the Weather Channel. The storm could drop nearly an inch of crippling ice in Nashville and 18 inches of snow in New York City, with many state officials warning of hazardous road conditions and dangerously low temperatures.

“It’s showtime,” Rohit Agarwal, the CEO of the site’s parent, the Weather Company...