UPDATE (Dec. 8): A winter storm watch has been issued.

UPDATE (Dec. 8): Forecasters are now calling for 4 to 6 inches of snow in much of South Jersey, from Ocean County down to Cape May County, and 2 to 4 inches of snow in most of central and northern New Jersey, except for Sussex and Warren counties.

A winter storm watch has been issued for the southern half of New Jersey, and a winter weather advisory has been issued for the northern half of the state, not including Sussex and Warren. The watch and advisory go into effect from 1 a.m. Saturday through 1 a.m. Sunday.

A storm system is now expected to move closer to the Atlantic coast than was initially anticipated, upping the probability that most areas of New Jersey will see their first snow accumulations of the season this weekend.

In a revised forecast issued Thursday afternoon, the National Weather Service forecast office in Mount Holly now calls for up to 4 inches of snow in far southern New Jersey, 3 inches in parts of Monmouth and Ocean counties and 2 inches or less from Middlesex County up through northern New Jersey.

"Light snow is expected to accumulate up to a few inches late Friday night through Saturday," the weather service said in a hazardous weather outlook issued at about 3:50 p.m. Thursday.

In a forecast discussion, the weather service said a coastal storm system that had been expected to remain far offshore Friday night into Saturday afternoon "is showing better organization today and also a track closer to the coast."

FIRST CALL: A costal system will impact the region late Friday into Saturday. A slight shift east or west will make a huge difference regarding snow totals and how far inland the snow will reach. Latest guidance is trending west. Stay tuned! pic.twitter.com/EybUe6MEjS — NortheastWeatherWx (@NEWeatherWx) December 7, 2017

During the past few days, computer forecast models have flip-flopped as to whether the storm would track close to the Jersey coast and bring several inches of snow or track further east and deliver only a dusting of snow -- or nothing at all. As of Thursday afternoon, all of the models now favor some accumulating snow across southern and central New Jersey as well as in parts of Delaware and Maryland, the weather service said.

UPDATE (Dec. 7): The National Weather Service's New York office is now calling for as much as 3 to 6 inches of snow across eastern Long Island and 2 to 4 inches of snow across New York City, northeastern New Jersey and western Long Island on Saturday.

First snow of the season?

If snow does fall and accumulate, it will be the first measurable snow of the season for every region of New Jersey, except for parts of Morris, Passaic and Sussex counties, which had light snow coating the ground in November.

Measurable snow is considered to be 0.1 inches or more. Anything less than that is considered a trace.

Most regions of New Jersey normally get their first taste of snow on Dec. 7 or later, according to statistics from the National Weather Service and New Jersey State Climatologist David Robinson, based at Rutgers University.

Accumulating Snowfall Returns For This Weekendhttps://t.co/ACwQjbayov pic.twitter.com/XsUOA8vY2k — NY NJ PA Weather (@nynjpaweather) December 7, 2017

A few places, like the northern hilly areas of Sussex County, usually see their first measurable snow -- 0.1 inches or more -- by Dec. 2. And some, like the West Milford area of Passaic County, get their first real taste of snow by Dec. 3.

People down in Atlantic City and Cape May usually have to wait until the third or fourth week of December to brush snow off their cars. In Atlantic City, the average date of the first snowfall is Dec. 19, and in Cape May it's Dec. 26.

Here are a few key points about the upcoming weekend snow event:

Here is the National Weather Service's snow forecast for New York City, northeastern sections of New Jersey and Long Island, as of Thursday night. In a post on Twitter Thursday night, the weather service's regional office in Upton, N.Y., noted: "There is still a good deal of uncertainty with the snowfall amounts, so stay tuned for updates!"

The Upton office oversees New York City, Long Island, parts of Connecticut, the lower Hudson Valley of New York and five counties in northeastern New Jersey: Bergen, Essex, Hudson, Passaic and Union.

The latest snow forecast for New York City, Long Island and northeastern New Jersey, as of Thursday night. (National Weather Service)

Note: This report was updated to include additional details about accumulating snow that fell in parts of Morris, Passaic and Sussex counties in November, and also updated to include snowfall forecasts that were revised Thursday night and early Friday morning.

Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com. Follow him on Twitter @LensReality or like him on Facebook. Find NJ.com on Facebook.