A winter storm will likely bring a few inches of snow to Boston on Tuesday, but not heavy accumulations.
On Monday morning, most model data showed a band of heavy snowfall stretching across parts of southern New England. The European model, though, had the storm further south. And as the day went on, other models started to show a similar path.
The shift means lower snowfall amounts all across Massachusetts. There will likely be a coating to 2 inches of snow north and west of I-495, 2 to 5 inches around Boston, and 4 to 7 inches south of the city. Along the Cape, wind gusts and snow accumulations up to 7 inches could lead to scattered power outages.
The Tuesday morning commute may feature rain in Boston before transitioning over to snow. And by Tuesday evening, the entire storm will have passed.
An intense but fast-moving weather system is going to impact the region Tuesday morning into the late afternoon before exiting Tuesday night.
This is likely to be Boston’s largest snowstorm in nearly two years!
All storms are different, and this particular one is notable for the intensity of the precipitation that is expected. Snowfall rates on the order of 1 to 3 inches per hour are likely at the height of the storm between 10 a.m. and 3 p.m. During this time I would recommend not being on the roads, as even plow trucks are going to have trouble keeping up with the rapidly accumulating snow.
I expect the first flakes — which may be in the form of a rain and snow mix — in Boston around 7 or 8 a.m. The final flakes should fall just after dark Tuesday.
The most intense band of snow will likely ride along Route 84 from Connecticut and then up along the Mass Pike. Those inside this intense band could accumulate 6 inches of snow in just a few hours, while those outside of the band in that same time frame may receive less than half of that.
The loop above is based on model data, so don't take the numbers literally — but you can see how narrow the band of heavy snow is expected to be. This is why it's so difficult to forecast the northern extent of the heaviest snow. A shift of just 30 miles makes an enormous impact on what you will end up shoveling.
When I am forecasting, I look at a whole suite of data in order to come up with those snowfall maps that you see. One piece of data, the European model — which is often very reliable — is indicating that this storm is going to miss us. It's difficult to rely on just one forecast from one model, but this model is also reliable enough that discounting it completely would be foolish. In other words: The forecast can still change, even at this late date, which is not typically what we see.
The map below is an ensemble forecast from the European model, showing the chances of having 6 inches of snow. Notice that there's virtually no probability, according to this model, that we're going to see heavy snow.
Winds will be strong on Cape Cod and the islands, and less so further inland. There could even be blizzard conditions on parts of the outer Cape in the afternoon Tuesday, but they would not be widespread.
In terms of coastal flooding, look for pockets of minor to perhaps moderate flooding during high tide, around 1 p.m. Tuesday. There may be near-flood conditions again on Wednesday, but this is because of the astronomically high tide.
Colder weather moves in for Wednesday with clearing skies.
Plow crews should have a relatively straightforward time of clearing the snow after the storm, as we don't have any existing snow on the ground.
Another system brings lighter snow to parts of the area Thursday night or Friday. This is followed by a dry cold weekend ahead.