Nasty weather had long loomed for parts of the Washington region for the Super Bowl on Sunday, but it had seemed that the District and nearby spots might skate by. Late Saturday, however, “skate” became ominous, as actual ice seemed more likely all over.

National Weather Service forecasters said their latest guidance indicated “significant potential for freezing precipitation” in the area. They said precipitation would probably start earlier and end later, with temperatures at or below freezing for longer.

“Be prepared for slippery roads and limited visibilities,” the Weather Service said, raising concerns that travel to see the game on TV could be as uncertain as the final score.