Ahead of weekend storm, we ask what makes Sussex County the 'snow capital' of NJ?

Northwestern New Jersey is looking at a snowstorm Saturday night, which could drop 6 inches of snow across the area, especially in the hills.

The exact path of the nor'easter is still a matter of several factors, but it appears the rain-snow line will be along I-95 with areas north of I-78, which crosses the southern edge of Warren County, getting all snow, according to the Thursday advisory from the NWS station in Mount Holly, which covers northwestern New Jersey and adjacent Monroe County in Pennsylvania.

Forecasters said the current predicted path of the storm will result in snowfall of 1-4 inches in the area between I-95 and I-78, and 4-6 inches north of I-78.

The forecast office in Binghamton, New York, which covers northeastern Pennsylvania and the Catskills of New York, is forecasting up to 9 inches of snow from this system, so areas of northern Sussex County could see more than the Mount Holly forecast.

There can be a wide difference between snowfall in the mountains of northwestern New Jersey and the rest of the state, said state climatologist David Robinson.

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As an example, his office's recap of a precipitation event on Dec. 11 showed just a bit of rain to most of the state. Yet, High Point Monument, at the state's tallest point at 1,800 feet, had 5.1 inches of snow. A definite snow-line could be seen that day along the rest of the Kittatinny Ridge, at about 1,200-foot altitude.

From that event, just a couple of miles away from High Point, a weather observer in Wantage had 1 inch of snow and in Hardyston, on the eastern side of Sussex County, another observer measured less than a half-inch of snow.

The uncertainty of snowfall amounts is because of the storm's track. Sussex County is forecast to be in the colder, northwest quadrant of the storm - resulting is now - while the rest of the state, even 50 miles away, will be under warmer air which will result in rain.

"The biggest question for forecasters is where is that rain/snow line?" he said. "Usually, it means Sussex County is in that cold quadrant, making it the 'snow capital of New Jersey.'"

This storm is following the path of typical nor'easters, so named because the storm follows a northeastern path along the coast, resulting in winds around the storm center being from the northeast as the storm spins counter-clockwise.

According to Robinson, the name was coined by Ben Franklin and his brother, James, in their letters between Philadelphia and Boston. As they wrote about the weather and storms, it became apparent that winter storms moved from Philadelphia toward Boston, or in a northeast direction. The two also noted that the wind direction was from the northeast.

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Meteorologists now know that nor'easters form because of a clash of the cold northern air and warmer air to the south or over the ocean.

"These kinds of storms like to percolate independently," explained Robinson, as a difference to hurricanes, which are created by warm ocean temperatures which fuel the storm.

Nor'easters are a version of storms formed from a clash of air masses and are at or just off the Atlantic Coast. The path of the storm is to the northeast and sometimes the storms form far enough off the coast that they miss the mid-Atlantic a just hit New England or the Maritime Provinces of eastern Canada.

Nor'easters are actually more damaging to the northeastern U.S. than are hurricanes because they are larger in size and more common. While a hurricane has winds of 74 mph and higher, nor'easters often have sustained gale force (58 mph) winds along the coast causing beach and shore erosion.

And, while a hurricane can extend to 300 miles in diameter, nor'easters are 3-4 times wider and slower to move on, sometimes lingering for days in an area.

The big difference is nor'easters thrive and pick up strength from cold air in the atmosphere, often coming from a dip in the jet stream coming from the Artic.

However, he said, nor'easters can form anywhere along the east coast and don't always follow the same tracks. As an example, such a storm two years ago dropped 10 inches of snow on south Jersey, but left northern Jersey dry as the storm passed to the east.

The advance forecast for later next week sees a "strong air pressure gradient" developing over the eastern U.S. with a departing low pressure center and an approaching high pressure system. That gradient will lead to potential for strong winds.

The forecast for the mid-week storm also notes a surge of deep moisture and warm air from the Gulf of Mexico moving northward ahead of the system, creating more "spin" in the atmosphere creating a storm system.

This article originally appeared on New Jersey Herald: Sussex County snow capital of NJ? Forecast says 6 inches possible