The Bottom Line

For this update, I will largely let my newly-drawn snow forecast map speak for itself. We're in the "sweet spot" now — for a good chunk of New Jersey, major snow accumulations are likely from Sunday afternoon through Tuesday.

Snowfall accumulation forecast for the Sunday-Monday-Tuesday nor'easter, as of Saturday morning. (Dan Zarrow, Townsquare Media)

I'd call confidence "moderate" at this point. A few model solutions this morning were puzzling, as they show a big northern shift in the track and totals. So there are still some question marks about how the storm track will ultimately "wiggle" as our nor'easter continues to move and develop. But the chance for a full "escape route" is pretty much off the table at this point.

The wind and coastal flooding picture is also very concerning.

Timeline

—Sunday Morning... Absolutely nothing. As our storm system approaches from the southwest, it's going to battle some very dry air over New Jersey. It will take a while for our atmosphere to moisten up enough to allow for precipitation.

—Sunday Afternoon... Scattered light snow arrives in southwestern New Jersey, spreading through the southern half of the state through about dinnertime.

—Sunday Evening... Snow continues spreading north, becoming a bit steadier and heavier after sunset.

—Early Monday Morning... As coastal low intensifies, strong northeast winds kick up. That will cause warming for coastal and southern New Jersey, enacting a change to icy mix and/or straight rain. For North Jersey, snow continues.

—Mid Monday Morning... The brunt of the storm begins. Bands of very heavy snow will cause quick accumulations and rapidly deteriorating road conditions.

The GFS model forecast around midday Monday, during the peak of the storm. Bands of heavy snow will impact much of NJ at that time. (College of DuPage Meteorology)

—Monday Afternoon... Heavy stuff continues. As temperatures crash, much of the mix/rain area in southern New Jersey will flip back to sleet/snow.

—Monday Night... Precipitation intensity starts to dial back around sunset. But it still looks wintry overnight, with additional light to moderate accumulations likely for all but the far southern coast.

—Tuesday Morning... Slowly but steadily, snowfall will taper off, from west to east.

—Tuesday Afternoon... Wrapping up. Let the shoveling begin!

Accumulations

—The "sweet spot" for this storm is currently forecast to be approximately on either side of the NJ Turnpike corridor. On my snow map, I labeled this as 8-12+ inches. The plus is important — if future model runs continue to support snowfall of 14, 16, and even 18 inches, I will adjust my prediction accordingly. Forecasting over a foot of snow requires a resounding amount of evidence, and I just don't think we're there yet. Yet.

—North of the snow bullseye, around Sussex and Warren counties, you may fall out of the heaviest snow bands. Still a wintry period of weather, especially since zero mixing is expected.

—In South Jersey and along the Jersey Shore, timing is everything. The longer the period of sleet and rain Monday morning, the lower the total snow/sleet accumulation will be. This contour (both the geography and magnitude of snowfall) is the least certain piece of the forecast.

—And for NJ's southern coast, you know it's hard to get a good snowstorm. And this one's no different. Once precipitation flips from snow to rain late Sunday night, it's going to be very hard to get back to frozen precipitation. Not impossible, especially as northerly winds prevail on Tuesday. Light accumulations and minor travel issues are a possibility.

Winter Storm Watch

The National Weather Service expanded our Winter Storm Watch to now include all or part of 20 of NJ's 21 counties. Here's the rundown:

—6 a.m. Sunday to 6 a.m. Tuesday... inland Atlantic, inland Cape May, Cumberland, Gloucester, and Salem.
—6 p.m. Sunday to 6 a.m. Tuesday... Burlington, Camden, Hunterdon, Mercer, Middlesex, Monmouth, Morris, Ocean, Somerset, and Warren.
—Midnight Monday to 6 a.m. Tuesday... Bergen, Essex, Hudson, Passaic, and Union.

As of Saturday morning, a Winter Storm Watch covers or all part of 20 of NJ's 21 counties.

We'll likely see the watch upgraded to warnings late Saturday or early Sunday. Less-urgent, less-severe advisories are likely for all the areas that fall shy of warning criteria
.

Additional Issues

Snow and ice and rain are absolutely not our only concerns from the impending nor'easter. Fierce northeasterly wind gusts to 50 mph are expected during the height of the storm on Monday, peaking in the morning. That will cause blowing and drifting snow, even further reducing visibility. (Blizzard conditions are not out of the question here.) Also, scattered to widespread power outages are likely — it's never fun to lose your power in the middle of a snowstorm.

In addition to the snow, the GFS model shows a very strong low-level jet about a mile overhead. That will result in fierce 50+ mph wind gusts at the surface. (College of DuPage Meteorology)

Furthermore, those strong winds will push a lot of water toward the Jersey coastline. We call that storm surge. And tidal guidance continues to show a solid 3 feet of surge along the oceanfront, and connected back bays and tributaries. That is generally enough to cause widespread moderate flooding of tidal waterways.

The latest tidal guidance for Atlantic City, NJ shows a precarious 3-foot surge on Monday. (NOAA / NWS / MDL)

As Jersey Shore residents well know, nor'easters are notorious for producing significant coastal flooding. (Remember Governor Christie's #Mopgate incident in January 2016?) Please be very conscious of where you park your cars and where you drive during and after the storm. The Monday morning, Monday afternoon, and Tuesday morning high tide cycles will be extra high. (With little opportunity for back bays to fully drain in between.)

Impacts

In the end, it doesn't matter if you see 6, 12, or 18 inches of snow. It all qualifies as "major snow" in my book. (In other words, yes it's a bread and milk storm!)

Road conditions will go downhill rapidly as the heaviest snow arrives during the day Monday. That will significantly impact New Jerseyans' ability to commute and travel. I suspect many schools in the "big snow" zone will cancel classes for Monday (and possibly Tuesday too). The trigger for superintendents to make that call would be after warnings are issued.

Action Steps

Carefully consider your plans from Sunday night to Tuesday morning. If Monday is your usual food shopping day (like me!), you might want to stock up on supplies ahead of the storm. Ready the shovels and snowblowers. And the kids' snowsuits and sleds too, of course.

What's Next?

After the 12Z model run comes out, I'll have a full update late Saturday. The snowfall forecast will likely shift a bit, hopefully becoming more specific. I also plan to dig deeper into the overall timing of the storm — discussing not only where the heaviest snow falls, but when. Hopefully that will be a helpful planning tool, with 24 hours of first flakes.

I'm also in the weather center all weekend, handling most of our on-air radio shifts. If you're out and about, you can tune in for the latest updates before, during, and after the storm. Or check out our handy-dandy mobile app — you'll be the first to know when important storm content is posted.

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