A Winter Weather Advisory is in effect for all 21 counties in the Garden State, as a transition from snow to wintry mix to rain will make roads slippery almost all day Saturday.

UPDATE as of Saturday 12/17 at 10:15 a.m.

Radar as of 10:15 a.m. Saturday. (Radarscope)

Temperatures continue to warm above the freezing mark across New Jersey. We're almost done with "snow" - a combination of the transition to wintry mix and rain, and also thanks to a dry slot moving into North Jersey from Pennsylvania.

Rain is still precarious though, as it's still "freezing" rain in many spots. That means the liquid raindrops freeze on contact with a cold surface, like snow, cars, roads, power lines, trees, etc.

Even as the precipitation winds down and advisories are allowed to expire, roadways will remain slick and perilous through at least part of the afternoon.

UPDATE as of Saturday 12/17 at 9 a.m.

Radar image as of 9 a.m. Saturday, showing an area of dry air approaching from the west. (NJWeather.org)

Even though the snow-mix transition has slowed down (read previous update below), we are starting to see the back edge of this band of moderate to heavy snow. As that arrives by Noon, we'll see a tapering of the precipitation, allowing the south-to-north warmup to accelerate. Once again, by this afternoon, snow and sleet will be done and any remaining precipitation will be rain.

Until the changeover is complete, and any snow/ice melts, travel will remain hazardous. The Winter Weather Advisory has been allowed to expire for southern New Jersey (Ocean, SE Burlington, Atlantic, Cape May, and Cumberland counties) as the transition to rain continues.

UPDATE as of Saturday 12/17 at 8 a.m.

Radar image as of 8 a.m. Saturday. Blue=snow, pink=mix. (Radarscope)

So far, our winter weather event has been following closely to the forecast timeline below. Sleet and freezing rain have been reported as far north as Middlesex County.

However, as of 8 a.m. the radar trend shows a band of heavier snow/sleet moving through Somerset, Middlesex, and Union counties. I believe that heavier precipitation has halted the warming trend temporarily. Snow totals are still trending well, heading toward the 2-4+ inch range along and northwest of Route 1. So no cause for concern yet.

Roads - especially untreated ones - are a mess. Plowing has been difficult so far, both because the snow isn't deep enough yet AND because it's so cold. Parts of North Jersey remain in the lower to mid 20s this morning. Road salt doesn't work below about 27 degrees.

Travel is treacherous, with major road closures and speed restrictions reported. Conditions won't improve until the warmer temperatures arrive later this morning into the afternoon!

It’s snowing!

Snow started to accumulate early Saturday morning in Union County. (Dan Zarrow, Townsquare Media)

At least, as of this writing, it’s been snowing for several hours across most of New Jersey. With upwards of 4 inches of accumulation expected in North Jersey, along with some ice accumulation, travel will bevery messy for at least the first half of Saturday. A warmup and eventual changeover to rain will put an end to the icing concerns later on.


The key to this forecast will be an influx of warmer air bubbling up from the south. Not only will the warmup put an end to our brutal cold snap, it will also force a transition from snow to a wintry mix of sleet/freezing rain by mid-to-late morning. And then, as temperatures spike to near 50 degrees later (by midday at the latest), all precipitation will turn to rain. Once the transition from snow to wintry mix starts, it should progress to all rain within 2 to 3 hours.

Here's how the day should shape up:
--Already occurring... areas along the southern coast (Atlantic, Cape May, Cumberland counties) begin transition from snow to mix
--Around the 7 a.m. hour... transition from snow to mix begins along the I-195 corridor, models show an overall increase in precipitation intensity after sunrise
--Around the 8 a.m. hour... transition from snow to mix begins along the I-78 corridor
--Around the 9 a.m. hour... transition from snow to mix begins along the I-80 corridor
--Around the 10 a.m. hour... transition from snow to mix begins in far North Jersey, changeover to rain underway in the southern half of NJ
--Around the 11 a.m. hour... changeover to rain underway for all but far North Jersey
--Around the 12 p.m. hour... almost all rain by this point, tapering to scattered showers through the rest of the afternoon

Snow Accumulations

We’re holding steady with our previous snowfall forecast:
--4+ inches in far North Jersey, especially north of I-80 and west of I-287
--2 to 4 inches in northern and central New Jersey, along and northwest of Route 1
--1 to 2 inches throughout the rest of Central Jersey
--Up to 1 inch for interior South Jersey, south of I-195 and away from the coast
--Little to no snow along the south coast

Ice Accumulations

Concern has been growing over the last day or two that the middle part of Saturday's wintry precipitation progression - sleet and especially freezing rain - could make for an even bigger mess due to ice. Anywhere from a trace to a quarter-inch of ice accretion will be possible. Keep in mind, it doesn't take much freezing rain and ice to make roads, sidewalks, steps, and driveways treacherous.

Furthermore, this morning's forecast models show the area of greatest ice concern has shifted south. So it's not just North Jersey under the gun anymore.

I don't want to pinpoint ice accumulations and icing potential too much. Just keep in mind things will be slippery all morning. And potentially through part of the afternoon too, even after the flip to rain.

Winter Weather Advisory

The National Weather Service continues a set of seven Winter Weather Advisory messages for New Jersey on this Saturday. Again, it's just an advisory - not a warning. That means hazardous travel conditions are expected. But at long as you stay smart, there's no significant danger to life or property from this wintry weather.

Advisory expiration times for each county (or partial county) vary, depending on when the wintry impacts (snow and ice) are expected to end. Those expiration times are subject to change, if extension or early expiration are warranted given current conditions.

Here's a rundown of the advisory timing:
--Until 9 a.m... Atlantic, SE Burlington, Cape May, Cumberland, E. Monmouth, Ocean
--Until 11 a.m... NW Burlington, Camden, Gloucester, Hudson, Mercer, Middlesex, W. Monmouth, Salem
--Until 2 p.m... Bergen, Essex, Hunterdon, Morris, E. Passaic, Somerset, Union, Warren
--Until 5 p.m... W. Passaic
--Until 6 p.m... Sussex

Action Steps

Use extreme caution if you have to drive anywhere on this Saturday morning. Until temperatures warm and conditions improve, roads will be some combination of snowy, icy, slushy, and wet.

Unless you live in far North Jersey where the highest snow accumulations are expected, you can probably skip the shoveling for now. The combination of rain and warmer temperatures will probably melt/wash away snow from pavement surfaces by later Saturday.

Send us your snow reports and photos!

Stay warm, stay safe, and stay tuned for updates until the final flakes have fallen!

Dan Zarrow is Chief Meteorologist for Townsquare Media New Jersey. Follow him on Facebook or Twitter for the latest forecast and realtime weather updates.