The NWS has upgraded the Winter Weather Advisory to Winter Storm Warning. Rightfully snow as much more snow is falling that was predicted

Sussex-Warren-Morris-Hunterdon-Somerset-Carbon-Monroe-Berks-
Lehigh-Northampton-Western Montgomery-Upper Bucks-
Including the cities of Newton, Washington, Morristown,
Flemington, Somerville, Jim Thorpe, Stroudsburg, Reading,
Allentown, Bethlehem, Easton, Collegeville, Pottstown, Chalfont,
and Perkasie
741 PM EST Sat Feb 17 2018

...WINTER STORM WARNING IN EFFECT UNTIL 4 AM EST SUNDAY...

* WHAT...Heavy snow. Total snow accumulations of around 6 inches
  are expected.

* WHERE...Portions of northern and northwest New Jersey and east
  central, northeast and southeast Pennsylvania.

* WHEN...Until 4 AM EST Sunday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Be
  prepared for significant reductions in visibility at times. The
  snow may fall at 1 to 2 inches per hour at times in parts of the
  region, resulting in rapidly deteriorating road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.