Discussion: The December 29-30 period has presented a general storm signal for some time now. And that’s all we’ve been advertising due to the complex setup of multiple northern stream shortwaves coming in from and around the Arctic trough…as well as the timing of any southern stream shortwaves that might try to phase up cyclonic energy. Over the last week or so the models have sprayed a variety of surface solutions including anything from a complete miss to an all out coastal blizzard. You might have seen a few social media pages run with the blizzard idea. Through time and experience, we’ve learned to monitor mid-to-long range storm signals using the overall pattern with a focus on ensemble guidance.
The analysis of ensemble guidance between this past weekend and today has told us a few things. A phase between the northern and southern energy has become less likely. The southern stream shortwave wants to race ahead of the northern stream shortwave with little-to-no interaction. With that said, there is still the northern-stream energy that is expected to pass over New Jersey on ~Saturday (Dec 30). This would mean a very cold snowfall with high-ratio accumulation from whatever liquid falls. Example: .1-.2 of liquid would result in a fluffy and powdery accumulation of 2-4 inches. That would be assuming snow ratios of 15-20:1. Right now, most signs are pointing towards this scenario.
Things could still change especially as energy is better-sampled over the next 24 hours. Any level of coastal enhancement (as indicated on the European ensembles) would bump up expected snow totals SE of the I-95 corridor especially for the SENJ coast. Snow ratios would lower due to a “not as cold” snowfall however liquid amounts would outweigh such and produce higher accumulations. I only see a small chance of this (let’s say 30%).
The most realistic expectation, given all current data and observations, is a light and scattered snowfall for most of Saturday. The kind of snow that you can sweep off of paved surfaces with a broom. This northern stream type event could vary from just a c-2″ accumulation or possibly higher (2-4″) if everything were to come together perfectly. Right now everything is leaning towards the former. No official snow map out yet but I wanted to let you all know where my thoughts are. If this was a textbook setup like the January 2016 blizzard then it would much easier to forecast. Heck we’d probably have a first call snow map out already. Bottom line is the cold is here to stay through at least the first week of January. The snow chances however are complicated.
Following this December 30 potential is another winter storm signal surrounding the January 3-4 period. We’re going to have to wait until the December 30 system moves out to fully address such. But we are watching it.
In English: The pipe-bursting cold should continue through this weekend and well into next week. Snowfall is possible this Saturday, December 30 (looks like a light and scattered event as of now). It’s the soft, fluffy and powdery kind of snow as seen in the above image. Points SE of the turnpike, especially the immediate NJ coast, would be favored for a little more snowfall due to possible weak coastal interaction. We then have another winter storm signal for the Jan 3-4 period (possibly significant). We’ve been discussing this in the premium forum and will begin sending premium hyper-local text notifications out tomorrow. The first public snow map for Saturday will be released tomorrow evening assuming the event does not trend even lighter. Have a great night and please be safe! JC
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Jonathan Carr (JC) is the founder and sole operator of Weather NJ, New Jersey’s largest independent weather reporting agency. Since 2010, Jonathan has provided weather safety and forecasting services for New Jersey and immediate surrounding areas through the web and social media. Originally branded as Severe NJ Weather (before 2014), Weather NJ is proud to bring you accurate and responsible discussions ahead of high-stakes weather scenarios that impact the garden state. All Weather. All New Jersey.™