PM Update: Snowstorm winds down, cold air funnels in

The first snowstorm of the year blanketed much of New Jersey and New York with a few inches of snow on Tuesday, leaving a wintry scene behind. Forecast snowfall totals were fairly accurate — with the general 2-4″ forecast throughout the area serving as a good indicator of what was to come. A brief burst of heavy snow early on Tuesday morning began the event which continued until the middle of the afternoon, before wrapping up as scattered snow showers. Some notable snowfall reports (still preliminary) include: Newark (2.2″), Kennedy Airport (2.0″), and Central Park (1.3″), all daily records for their locations.

A photo taken by Doug Simonian during the heavy snow burst at 10:30am in Rockville Centre, NY.

A photo taken by Doug Simonian during the heavy snow burst at 10:30am in Rockville Centre, NY.

We will post a separate article sometime tonight or tomorrow recapping the event which will have final snowfall totals, a photo gallery, and a brief analysis as far as what went right and wrong with the forecast. Although for the most part, the snowfall forecast verified, a few spots did not receive as much snow as they could have, due to surface temperatures hovering between 32 and 34 degrees, rather than in the upper 20s to around 30.

Tonight, as the storm system exits stage right, some serious cold air will begin to funnel into the area. Temperatures, both aloft and at the surface, will respond to this changing airmass and arctic intrusion — and the snow cover will help low temperatures plummet tonight. Overnight lows will fall into the teens across much of the interior and real-feel temperatures will fall into the teens in the city as well. Be aware of black ice potential on area roads, as any standing water may quickly freeze over. Wednesday morning will certainly be a shock to the system, and will feel quite wintry!

Today's 18z GFS valid for tomorrow morning shows low temperatures primarily falling in the teens in the interior, and low 20s in the city. Temperatures on Long Island will be a bit colder than what this model is showing -- probably in the low 20s as well. Image credit goes to weatherbell.com.

Today’s 18z GFS valid for tomorrow morning shows low temperatures primarily falling in the teens in the interior, and low 20s in the city. Temperatures on Long Island will be a bit colder than what this model is showing — probably in the low 20s as well. Image credit goes to weatherbell.com.

Beyond Tuesday Night, the rest of the week looks to feature below normal temperatures but generally pleasant weather. The multiple disturbances associated with a frontal boundary near the region will have slid east-northeast, and the frontal boundary well offshore. This will allow for high pressure to build in, and a new airmass (of arctic origin) will settle in to the area.

But by later this week, intrigue will again increase as another mid and upper level disturbance tracks from the Central United States towards the Northeast and Mid Atlantic. Owing to this disturbance, a low pressure system is forecast to initially track towards the Ohio Valley. Eventually, a secondary low pressure will redevelop to the east, forced to do so by a strong high pressure to the north and cold air holding firm over New England.

Today's 12z European model valid for Saturday morning shows a 1039mb (strong) high pressure system in SE Canada, leading to an initially very chilly airmass as a storm with plenty of moisture gets going in the Tennessee Valley. Image credit goes to weatherbell.com.

Today’s 12z European model valid for Saturday morning shows a 1039mb (strong) high pressure system in SE Canada, leading to an initially very chilly airmass as a storm with plenty of moisture gets going in the Tennessee Valley. Image credit goes to weatherbell.com.

Forecast models are struggling, still, with the placement and strength of the redeveloping surface low as well as the strength and track of the primary low. This obviously will have major implications on the forecast in our area, and as such precipitation amounts and type remain highly uncertain.

Should a stronger primary surface low prevail, initial cold air would provide a period of frozen precipitation but would eventually be pushed out and overcome by warmer air both aloft and at the surface. Should the secondary low redevelop faster, stronger, and farther south — colder air would remain entrenched in the area, increasing the probability of a winter storm with plenty of snow, sleet or ice.

Today's 12z European model valid for Sunday morning shows secondary redevelopment being forced to our south, with plenty of snow for most of the region. That high pressure did slide out to sea, which changes coastal regions to rain after several inches of snow from overrunning, while the interior gets an all-out snowstorm. Image credit goes to weatherbell.com.

Today’s 12z European model valid for Sunday morning shows secondary redevelopment being forced to our south, with plenty of snow for most of the region. That high pressure did slide out to sea, which changes coastal regions to rain after several inches of snow from overrunning, while the interior gets an all-out snowstorm. Image credit goes to weatherbell.com.

Additionally, the exact timing of this high pressure system is important, which somewhat correlates to the strength of the primary low. If that high pressure in SE Canada slides out to sea too quickly, it will help to bring milder easterly winds off of the Atlantic Ocean and change our area to rain, and provide a pathway for the storm to cut to our west. If the high pressure can work its way into SE Canada a bit later and slow down, then it will be directly overhead when the heavier precipitation is arriving, which leads to the potential of a strong frontogenesis-forced snow band, like the Philly area saw on December 8th — only this time, it would be more expansive due to the storm’s moisture source being a bit more organized. This would also force secondary redevelopment to the south.

All of these scenarios remain on the table at this juncture, and confidence in any one of them remains rather low. Without any true high-latitude blocking, it’s hard to imagine the scenario playing out where the entire area (including the coast) sees a major snowstorm. But confidence in an event alone seems to be rapidly increasing, with forecast models coming into agreement on the disturbance, which will have plenty of moisture and run into a good, pre-existing cold airmass — which may give some of the area snow, even if the storm ultimately takes an unfavorable track for snow and changes the area over to sleet, freezing rain and rain.

Stay tuned over the next few days for further information as we continue to analyze the potential.

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