Melissa, if you have to drive, I, too, hope you are to your destination before it gets bad!
Here in my area (I'm approx. 17 miles slightly east but mostly south of Philadelphia), the time frame for starting is anywhere between 4 & 9pm, depending on what tv station you listen to. They did say only 40% chance of snow during the afternoon hours, steadier stuff after 9pm I think. Supposed to end around 7pm Saturday, with the worst occurring between 9am & 3pm Saturday.