A winter weather advisory has been issued for much of the tri-state area in anticipation of light freezing rain Friday night into Saturday morning. Areas north and west of I-95 will be most susceptible to a thin glaze of ice on the ground early Saturday morning. After a chilly but dry Friday, clouds increase later in the afternoon and precipitation will ramp up at night. Temperatures aloft are above freezing, so the precipitation will develop as rain. But surface temperatures will vary through the tri-state, which means different things will happen once the precipitation hits the ground. Overnight – most likely after midnight – surface temperatures in the advisory area will dip below freezing. When that happens, the rain that falls will freeze on contact with whatever surface it hits (hence why it is called freezing rain). Expect a thin glaze of ice on untreated sidewalks, driveways, roads and bridges. We won’t get a thick layer of ice, so tree limbs should be unharmed. At best, we’ll get a few hundredths of an inch. But when it comes to ice, the very thinnest of glazes make driving treacherous.  Don’t be fooled: A glaze of ice on a road or sidewalk looks exactly like wet pavement. You only realize it’s ice when you slip and fall or your car slides out of control, so assume it’s ice and not water. Any untreated roadways, sidewalks, steps could become slick. The best course of action, if possible, is to stay off the roads until temperatures warm above freezing and the glaze melts Saturday morning.  If you must get out, though, allow for extra time to get to your destination and drive very slowly. The areas closer to the coast, including New York City, will remain above freezing. In those spots, icing will not be a concern. The main risk area will be in central and northern New Jersey, the Catskills, Hudson Valley and inland Connecticut. Basically, all areas north and west of the I-95 corridor. Those areas will dip to below freezing overnight. You may wonder why, if the temperature drops below freezing, we wouldn’t get snow instead of freezing rain. The type of wintry precipitation we get, unfortunately, takes more into account than just surface temperature. Temperatures aloft are critical in determining what type of frozen precipitation falls. In the case of freezing rain, the air above the surface is above freezing, allowing the precipitation to fall as a liquid. Only a thin layer of sub-freezing air is nestled close to the surface. That causes the liquid to freeze once it hits the surface, creating freezing rain. With a slightly thicker layer of cold air, the liquid would freeze before hitting the ground, resulting in sleet. Thankfully, any ice that does fall will not be sticking around too long. Temperatures everywhere in the tri-state will be back above freezing by Saturday afternoon, and will continue to rise from there. From that point through the end of the year, precipitation chances are going to be all rain. The next round of rain will arrive later Sunday. Winds get gusty, too, and even more so on Monday — a combo that could be more problematic for travel, including at airports in the northeast. Anyone looking to head back home after spending the holidays in the tri-state, or those looking to head in for New Year’s celebrations, face the potential for delays due to the weather. The third round of rain comes just in time for New Year’s Eve celebrations. Anyone joining the crowds at Times Square should bring a poncho and be prepared for wet weather. Temperatures for when the ball drops will be chilly, but at least above freezing, in the 40s. In total, all the rain adds up to about 1-2 inches, with some locally higher amounts north and west. Though the month of December has had its fair share of rain chances, the area is still trying to recover from the drought conditions from this fall. Year to date, the tri-state is still running nearly four inches below average rainfall totals. It’ll be good to put a dent in that deficit before the year ends. The steady rain combined with the mild temperatures will wipe out any remaining snowpack in our region. In areas like northwest New Jersey and the Hudson Valley, where a few inches of snow are still on the ground, minor river flooding is anticipated. The quick influx of melting snow along with the steady overnight rainfall will contribute to the rise of rivers and streams, leading to some minor flooding, especially in low-lying and flood-prone areas. Average high temperatures this time of year are around 42 degrees. But it has been a week since we’ve seen temperatures even reach the 40-degree mark in Central Park. In terms of departure from average temperatures, December has been our coldest month so far this year. Rain will leave the area in time for the new year, but on its heels will be another stretch of cold weather. High temperatures are back near freezing by the start of next weekend.