Up to 15 inches of snow is forecast through Friday under a winter storm warning from the National Weather Service , with the heaviest snow due overnight and a switch to rain possible before the storm wraps up.

Where Is the Warning in Effect?

The NWS Anchorage winter storm warning covers the Northern Susitna Valley in Alaska from 1 p.m. Thursday to 2 p.m. Friday AKDT. Chulitna, Broad Pass and the Denali Highway are named inside it, and the office singles out one road in particular:

“Travel could be very difficult, with low visibility and rapidly accumulating snow along the Parks Highway.”

The Parks Highway is the main road between Anchorage and Fairbanks, and the stretch through Broad Pass sits right in the warning zone. Totals are forecast at 7 to 15 inches, with visibility of one quarter mile or less at times.

How Much Snow Falls Before the Warning Starts?

A fair amount.…