As much as 9 inches of snow has already fallen in some areas of northern New Jersey as of late Saturday night, and several other locations have already measured a half-foot of snow on the ground, according to preliminary snowfall reports from the National Weather Service. One town, in Warren County, has 10 inches of snow piled up on the ground in what is shaping up to be New Jersey’s biggest snowstorm in more than a year. And snow continues to fall in northern counties, with some clusters of flakes dropping from the sky at a rate of 1 to 2 inches per hour, the weather service and other meteoro…