We reached a high of 35 at Philly International shortly before 2pm after having some snow showers push through(and only amount to a trace of snow) on your Thursday. This was all associated with an Arctic cold front pushing through and the winds were gusting out of the west and northwest between 15-20mph.
Overnight the winds relax and with high pressure on top of us we'll have a clear night. Lows will be in the upper single digits to the lower teens in Center City(by the way, the record low at Philly International is 9 set back in 1934 and I feel that's pretty safe).
After a very frigid start we'll have a frigid day despite plenty of sunshine as highs will just be in the lower 20s. The wind will be out of the northwest between 5-10mph so there will be a wind chill in the middle teens. After a night in the middle teens we'll have sunshine give way to clouds late in the afternoon with highs in the upper 30s as a first area of low pressure pushes to the north. Another area of low pressure will ride along the Appalachians and provide snow to a mix then to rain as temperatures will rise from around freezing to the upper 30s. There may be prolonged mixing taking place depending on how long colder air sets up at the surface and how much warm air aloft sticks around; I can't even fathom putting up a snowfall map at this time and especially when model guidance is still all over the place.
Just remember that you can check the rest of the 7-day forecast(any time) at www.scottderekwx.com/forecast.html.