Commercial vehicle restrictions will be in place on several highways as the storm moves in, state officials said.
A heavy glaze of ice and sleet spread into the Garden State Friday night as the snow total forecast dropped, the National Weather Service said.
A state of emergency was declared in all 21 counties at 1 p.m.
"Starting this afternoon, we will experience a severe winter storm bringing dangerous outdoor conditions to our state,” Acting Governor Tahesha Way said. "This storm will cause dangerous road conditions and impact holiday travel. We are urging travelers to avoid travel during the storm and allow crews to tend to the roads."
"Drivers should plan their travel accordingly, monitor conditions and road closures, and follow all safety protocols," Way said.
Commercial vehicle restrictions will take effect at 3 p.m. on Interstates 78, 80, 280, 287, and Route 440, state officials said, and applies to tractor-trailers, empty CDL trucks, RVs, motorcycles, and passenger vehicles pulling trailers.
The new snow totals from the NWS show a potential of up to eight inches in Sussex and Morris County but the widespread totals have dropped to 1-3 inches.
The storm predictions were disrupting air travel on Friday, with dozens of flights being delayed or canceled at Newark Liberty International Airport. Read more:
Winter weather advisories, beginning 3 p.m. Friday through 10 a.m. Saturday, remain in place for coastal Monmouth County, along with Hunterdon, Mercer, Ocean, Burlington, Camden, Salem, Gloucester, and Cumberland counties. Atlantic and Cape May counties are not under advisories as of Friday morning.
".Travel could be very difficult," the weather service said. "If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency."
In the central and southwestern portions of the state, the mix of snow and sleet will make for slippery driving conditions.
The latest timing of the storm is below.
North Jersey
Friday night: Snow, possibly mixed with sleet, becoming all snow after 11 p.m. The snow could be heavy at times. Low around 21. Southeast wind 5 to 10 mph. Chance of precipitation is 100 percent.
Saturday: A chance of snow, mainly before 9 a.m. Cloudy, with a high near 30. Northeast wind 5 to 10 mph. Chance of precipitation is 40 percent. New snow accumulation of less than a half inch possible.
Saturday night: Mostly cloudy, with a low around 17. Calm wind.
Sunday: A chance of rain after 1 p.m. Mostly cloudy, with a high near 36. Calm wind becoming southwest around 5 mph. Chance of precipitation is 50 percent. New precipitation amounts of less than a tenth of an inch possible.
Central Jersey
Friday night: Rain, snow, and sleet before 3 a.m., then rain likely, possibly mixed with snow between 3 a.m. and 4 a.m., then a chance of rain after 4 a.m. Low around 28. East wind around 5 mph. Chance of precipitation is 100 percent.
Saturday: A chance of rain and snow before 7 a.m., then a chance of snow between 7 a.m. and 2 p.m. Cloudy, with a high near 36. Northeast wind 5 to 10 mph. Chance of precipitation is 40 percent. New snow accumulation of less than a half inch possible.
Saturday night: Mostly cloudy, with a low around 24. Calm wind.
Sunday: A chance of rain after 1 p.m. Cloudy, with a high near 40. Calm wind becoming southwest around 5 mph. Chance of precipitation is 50 percent. New precipitation amounts of less than a tenth of an inch possible.
South Jersey
Friday night: Rain and sleet, possibly mixed with snow before 2 a.m., then a chance of rain. The sleet could be heavy at times. Low around 31. East wind around 5 mph becoming northeast after midnight. Chance of precipitation is 90 percent. New snow and sleet accumulation of less than a half inch possible.
Saturday: A chance of rain, mainly before 9 a.m. Cloudy, with a high near 39. North wind 5 to 10 mph. Chance of precipitation is 30 percent. New precipitation amounts of less than a tenth of an inch possible.
Saturday night: Mostly cloudy, with a low around 25. North wind around 5 mph becoming calm.
Sunday: A chance of rain after 1 p.m. Cloudy, with a high near 44. Calm wind becoming south around 5 mph in the afternoon. Chance of precipitation is 40 percent. New precipitation amounts of less than a tenth of an inch possible.
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