The next storm will arrive later in the day Sunday. It might start as a mix, but then go all liquid on Sunday night. Northwest of Philadelphia, you could see a prolonged period of a wintry mix.
In the wake of that storm, another bitterly cold airmass will invade the region on Monday and Tuesday, and temperatures on Tuesday might actually turn out COLDER than today with highs of 10-15 degrees.
However, I will leave you with some good news. We could see milder temperatures by mid-January as the January thaw tries to kick in.