Pennsylvania Gov. Josh Shapiro signed a disaster declaration for the state ahead of Sunday’s blizzard.

“I just signed a disaster declaration ahead of this evening’s storm — making sure our state agencies have every resource they need to prepare and keep people safe,” Shapiro wrote on X.

“As snow is expected to intensify this evening, avoid unnecessary travel and follow instructions from @PEMAHQ, @PennDOTNews, @PAStatePolice, and your local officials,” Shapiro further wrote.

Conditions are expected to begin to worsen in the Philadelphia area later today, the governor said in a press conference Sunday afternoon.

Shapiro asked people to stay off the roads and also to stay indoors during the storm, which forecasters expect to dump between 12 and 18 inches on Philadelphia and coastal areas.

-ABC News’ Victoria Arancio