By Meteorologist John Cifelli
Monday was a transition day, as we began the day mild before a cold front swept across New Jersey in the afternoon. At 3 p.m., temperatures were above 70 just west of Atlantic City, and had dipped below 40 in Sussex County, providing quite the contrast. Temperatures are headed for the 20s and 30s tonight, and our next day of winter weather arrives on Tuesday.
This event is known as an “overrunning” event, when a slug of moisture associated with upper level wind flow spreads precipitation over the area, devoid of a significant low pressure center at the surface. These setups can be responsible for significant icing events in New Jersey, and I think that is likely the biggest threat tomorrow.
Light rain will continue in far southern New Jersey overnight Monday, and showers will gradually spread over the rest of the state throughout the rest of the day. I should say very gradually, as we are drying out further north in response to an abnormally powerful area of high pressure over eastern Canada. This high pressure center will encourage low level cold to remain in place in northern New Jersey, and so as precipitation lifts north, I think we see rain transition to a wintry mix north and west of the 202 corridor. Warm air follows behind the front edge of the precipitation, and so frozen precipitation will be short lived and a non-issue for the majority of the state.
North of Route 80, there may be some icing in the late afternoon, coinciding with the evening rush hour. Precipitation will be light and surface temperatures right around freezing. If it is raining instead of snowing, this will likely cause some issues for northern Warren, Sussex and Passaic counties. Anyone in this part of New Jersey should check road conditions before driving, and remember that in these marginal temperature situations, roads could be wet in one town and icing over a few miles away. Take it slow if you are out and about in far northern New Jersey tomorrow afternoon and evening.
Eventually it warms above freezing even in far northern New Jersey, and after rain showers overnight statewide, we gradually dry out by the end of the day on Wednesday. Seasonal cold will follow for the rest of the week thereafter during a relatively quiet first week of December.