The second powerful winter storm in five days is on the doorstep of New Jersey Tuesday evening. Already some rain showers knock on our doorstep, pressing north from the Delmarva Peninsula and eastern Pennsylvania. We’re quickly cooling off also, as the low levels of the atmosphere close to the surface saturate.
To our west, the primary low south of the Great Lakes is fading, and as upper level energy swings across the Appalachian Mountains, a coastal low will form and strengthen just southeast of our coast this evening. The coastal low will slowly trudge northeast tomorrow, moving from a point just southeast of Cape May to southeast of Long Island, 12 hours later. That gives the system plenty of time to rake the state with bands of heavy rain and snow, before precipitation winds down late Wednesday night.
Expect showers to begin before midnight tonight. North of Route 202, precipitation will begin as snow, but it is more likely to be rain in Central and Southern New Jersey. Central New Jersey changes over the snow in the pre-dawn hours of Wednesday, but I don’t think too much accumulates overnight. Surfaces are warm and snowfall intensity is light overnight, so perhaps we will see a slushy inch to start on grassy surfaces and cars. Shortly after daybreak, things will escalate quickly.
Heavy rain with a few embedded rumbles of thunder will surge north and west off of the Atlantic into the colder air across the northern half of the state. As mid-level lows aloft deepen just off the coast, bands of precipitation will produce very heavy snow for several hours. Heavy, wet snow falling at 1 to 2 inches per hour looks likely in these bands, which could be anywhere from eastern Pennsylvania to the New York City metro area. Traveling in the northern half of the state late morning through mid-afternoon north of I-195 will be difficult or nearly impossible, with poor visibility and roads snowed over more quickly than they can be cleared. That’s the first focus of the forecast, where the heaviest bands set up.
The other challenge is the rain/snow line. As usual, it’s expected to straddle the Turnpike corridor. I think that New Jersey suburbs of New York will see a bit more than those of Philadelphia, but if the coastal low takes a more northerly track off our coastline, warm air will nose in off the ocean and make things more wet than white. This scenario would also allow colder air to more quickly wrap around the back side of the low into Pennsylvania, which would allow snow to more readily accumulate here. As usual, a subtle shift in the track of 20 to 30 miles will make a world of a difference for this heavily populated part of the state. It sounds like a cop out to mention this, but it is important to keep in mind that just north and west of the cities is where the topography becomes more elevated and it is easier to support snowfall. It’s just the lay of the land in these parts.
Speaking of elevation, I think similar to Friday’s nor’easter, that the highest parts of Sussex, Morris, and Passaic Counties again achieve the largest totals. All of northern New Jersey is in line for a major snowfall, with less the further south and east you go. Cape May, Cumberland and Atlantic Counties may not even see a coating on the backside of the system as it pulls away.
Winds will not be as widespread problematic as they were with last week’s storm. The snow will be wet and heavy, and trees will come down under the weight, especially with gusts over 30 mph. With some residents still without power from last week’s storm, this storm will only exacerbate these challenges.
By Wednesday night, precipitation is wrapping up from the southwest to the northeast. That will give road crews the night to clear, and we will wake up Thursday to sunny skies. After digging out and melting off some snow under the strengthening March sun, we should be back to normal relatively quickly, power failures notwithstanding. The rest of the week looks seasonal and dry.