In just over 24 hours, we’ll see the beginnings of our first major winter storm start in New England. By about 9-10:00pm on Saturday night, flurries and light snow will begin to fall. If you have plans Saturday night, you should be ok. The heavy snow will start around midnight and will hit like a wall. Heavy snow at rates 1-2″ per hour will develop and last for most until around 6am.
After 6-7:00 am, a good chunk of us will start to see the snow change over to sleet and freezing rain and stay like that for much of the day. For that reason, the main snow accumulations will occur during that midnight to 6am window. North of Route 2, the precipitation will stay as snow for much of the day with brief periods of sleet, so snow accumulations will be significantly higher. The sleet and snow will continue into the early afternoon. As the low exits, it will start to pull in cold air and give us all one last push of snow, maybe adding an inch or so to the accumulation totals.
Total accumulations will drop off pretty dramatically south of Route 2 as more sleet will mix in during the day. While areas in Southeastern Mass will see significantly less snow, the icing will become more of a concern. Freezing rain is likely or even plain rain at times. With the freezing rain, obviously that would lead to slick surfaces, but as temperatures drop Sunday afternoon, we’re concerned about a flash freeze. Bitter cold air will rush in from the north and freeze everything solid. So it’s best if you can shovel early and often to avoid removing/chipping away at solid ice chunks Sunday afternoon.
Finally the threat of wind and coastal flooding, while low, is not zero. Coastal areas could see winds gust to 45 mph at times. Those stronger winds combined with high tide could lead to flooding on low lying roads or susceptible basements. Cape Cod and the Islands are under a Coastal Flood Advisory for minor coastal flooding potential, while Boston, South Shore, and the North Shore are under a Coastal Flood Warning for moderate flooding potential. The concern for this would be during the Sunday morning high tide, which occurs around 10 am and about 2 hours on either side of it — so 8am until noon Sunday.
