It’s Here – The First Accumulating Snow of the Season

You can’t put it off any longer. We warned you on Monday that it was coming. The inevitable has arrived. Our first measurable snowfall of the season is knocking on the door. For those of you that hate snow – we apologize in advance.

gfs.prateptype_cat.us_ne.2017120812-loop
GFS model forecast for the progression of our system on Saturday. Image provided by Pivotal Weather.

It’s our first storm of the winter, and it shouldn’t be a big deal. The good news is, it’s going to happen over the weekend, which will minimize problems on the road. The number of people around here that can’t drive properly to begin with is already fairly high, and when you add precipitation into the mix, that number increases. Add in wintry precipitation, and the number increases even more. So, to have most of the snow fall during a Saturday evening/night will keep the number of people on the roads to a minimum.

The front that moved through here a few days ago, bringing an end to our mild weather, stalled out offshore. A wave of low pressure will ride along it this weekend, strengthening as it moves over the Atlantic south and east of the region. This is fairly typical, and how we get a lot of our snow events in the winter. It should spread precipitation into the South Coast by daybreak Saturday, spreading northward across our area during Saturday morning and early afternoon. Snow will quickly change to rain across Cape Cod, with a change to rain also expected right along the eastern coast and across parts of southeastern Massachusetts. Water temperatures are still well into the 40s, so any wind blowing off the water will bring milder air into coastal areas. Winds won’t be that strong, and they’ll be more northerly than northeasterly, which will likely prevent the warmer air from penetrating too far inland. As winds shift into the northwest behind the storm early Sunday morning, this will likely change the rain back to snow, even at the coast and across much of the Cape.

So, how much are we looking at? The map below is a close approximation, but we’ll break down a bit farther:

Cape Cod: Little to no accumulation.
Coastal SE Mass/Cape Ann: 1″ or so, maybe 2″
Interior SE Mass/Providence/Boston/North Shore/Seacoast: 2-4″
Much of the rest of Eastern Mass/Southern NH/Northern RI: 3-6″

We do think a few places could see 7 or even 8″ of accumulation, with the best chance of that happening from the hills in NW Rhode Island into Worcester County and possibly parts of the Merrimack Valley.

gfs_snow_Ku_acc_boston_9
Snowfall forecast from the GFS model. This closely matches our thinking for how much snow is expected. Image provided by WeatherBell.

 

 

Even though the snow will start by midday, it might not stick to pavements right away. Ground temperatures are getting colder, but pavements are a bit warmer, and having cars on the roads will keep the temperatures up a bit due to the friction. Once some steadier snow moves in, that won’t matter as much. So, if you’re heading out Saturday afternoon or evening, especially north and west of Boston, be careful. Hopefully, road crews will be ready for this, since it is the first storm of the season.

Once this system goes by, we’ll turn our attention to the next one on Tuesday. There’s still plenty of disagreements among the models on that one, so we’ll get into more detail in our Monday morning Outlook.

One thought on “It’s Here – The First Accumulating Snow of the Season

  1. Corina December 8, 2017 / 11:55 am

    It was bound to happen ,thanks for the update

    Like

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