It’s a cold morning across the region, with winds continuing, but not damaging. Wind chill is going to be running below zero for much of the day, although we’ll experience the coldest air the first few hours after sunrise. Later today, highs will reach the mid teens (20s over Cape Cod). If Boston doesn’t reach 18, which is a distinct possibility, then this will be the lowest daily maximum temperature recorded for Dec. 16.
The cold air is an important piece of the forecasting puzzle this weekend. A warmer air will move north overnight and Saturday, riding up and over the dense cold air at the surface. This will create what we call lift, and produce clouds and snow. Because cold air is heavy, it’s tough to move, and will lead to snow lasting for several hours Saturday morning.
Eventually the warm air will win out and change the snow to rain, but most of the precipitation will have already fallen, especially away from the coastline. This means we can expect a plowable storm with up to five or even six inches of snow in certain areas. The map below gives a general idea of what you should end up with in terms of snowfall, depending on where you live. I will be updating these maps on Twitter @growingwisdom throughout the storm.
Saturday night will bring some drizzle, or perhaps a few showers, but you should be able to get around and go out if you have plans.
Sunday will be a mild day with highs in the upper 40s and lower 50s. Anticipate lots of melting. The cold air will rush back in Sunday evening, quickly freezing any leftover slush, so be sure to remove it or it will be there for a while.
Cold Arctic air will return on Monday, but it won’t be as cold as it is this morning.
And with that, let’s talk about your weekend plans:
If you’re going running…
Saturday will be snowy in the morning and damp in the afternoon. The best time to run might be on Sunday—it will be mild into the early afternoon, but watch out for a few showers.
If you’re skiing…
Plan on changing weather conditions throughout the weekend. Ski country will see three to six inches of snow on Saturday, with some rain on Sunday morning. Highs will be cold—in the 20s—on Saturday, and much milder—in the lower 40s—on Sunday.
If you’re gardening…
Don’t brush off plants that are covered with snow; the cold makes them brittle and easily breakable. Wait until it becomes warmer.
If you’re running errands or going holiday shopping…
Expect snowy roads on Saturday, especially in the morning. This isn’t a storm you can’t drive in, but I would plan for extra time to get around.
I will be updating the forecast on Twitter @growingwisdom throughout the weekend.