NJ Winter Storm Watch: A delicate balance between track and temps
My number one goal as a meteorologist is to provide the most honest, accurate forecasts I can. I work very hard to make sense of the occasionally nonsensical inexact science of weather, so that you can adequately prepare for messy or dangerous conditions.
Having said that... Honestly? I hate this weekend's winter storm with a passion.
I have made two notable changes to the going snow forecast:
1.) Decreased max snowfall slightly.
2.) Pushed snow contours southeast, which lowers totals in NW NJ and pushes more of Ocean and Burlington counties into the appreciable snow zone.
In addition, inland Monmouth County has been added to the Winter Storm Watch, in effect for all or part of 13 NJ counties from Saturday evening through Sunday morning.
There are a few significant issues preventing meteorologists (not just me!) from compiling a truly confident, coherent forecast for this weekend's winter storm. Rather than regurgitate the latest nitty-gritty of the forecast, I want to talk about why this storm is such a pain in my rear, so you can understand how it may act.
For forecast detail like totals and timeline, refer to the map above and/or my Friday morning weather blog post. (I'll publish another comprehensive forecast article Saturday morning.)
The Coldest Temperatures Stay North
We always knew temperatures would be a problem. If thermometers were to end up 5 degrees colder OR 5 degrees warmer, this forecast would be tremendously easier.
32 degrees. The magical freezing mark. Nowhere on the temperature scale does the difference of a single degree have such a big impact on the weather forecast. Conditions could be drastically different if the temperature is 31, or 32, or 33 degrees.
It's really only safe to say the following: The coldest spot in NJ will be to the northwest, where this storm will probably deliver all snow. The warmest spot in NJ will be along the south coast, where this storm will likely produce mostly rain. Somewhere in the middle, there will be a line between wet and winter. My snowfall forecast map represents my best educated guess of where that line is most likely to end up.
The Strongest Forcing Remains Off-Shore
Compounding the temperature issue is the fact that the best lift and strongest forcing (i.e. the strongest part of the storm and heaviest bands of precipitation) are expected to stay just east of the Jersey Shore. This is the one element of this forecast that all the models actually agree on!
So the coldest air stays northwest. And the heaviest precipitation stays southeast. They're out of phase — not a recipe for big snow!
However, could there be a sweet spot where cold-enough air and heavy-enough precipitation meet to produce heavy snow? Yes, I think so.
The Bust Potential is High
Model consensus for this storm has been poor all along — heck, it didn't even show up in the forecast until midweek. The latest data shows two possibilities: a heavy hit of snow for interior New Jersey, and (ready for this) hardly anything at all.
That's right. Even more so than usual, I am worried about a complete bust of this snow forecast. For several runs — I've lost track of just how many — the GFS model has shown a warm solution, with very little snowfall. (No more than an inch or two.) It would be foolish to completely ignore such consistency.
I've tried to remain on the conservative side of snowfall forecasts, for good reason. To be clear, I wouldn't put out a snowy forecast like this if I didn't think it was going to happen. There's just always that nagging voice in my back of my mind, especially loud in borderline, on-the-edge, fringe cases like this setup.
The Bottom Line
In the end, I fully stand by the snowfall forecast I have published here. And I'm reasonably comfortable with it, because I believe there is a 50% chance totals will end up higher and a 50% chance we'll get less snow than expected. (My definition of a "good" forecast.)
Realistically, it doesn't matter how much snow ends up on the ground. Whether you see 0 or 9 inches of snow accumulation, whether it's mostly snow or mostly rain, our weather is going to be really messy from Saturday evening through early Sunday morning. There's the takeaway message from this forecast: Travel is going to be very difficult during the peak of the storm, around 10 p.m. Saturday.
Thanks for reading my analysis/rant. I'll take one more stab at this winter storm's timeline and totals with a fresh, comprehensive weather blog update by 8 a.m. Saturday morning.