It’s been a pretty typical December so far, one of about average snowfall and temperatures.
Of course, averages are made up of extremes, and we are entering a period of extreme weather over the next several days. This period is going to bring the coldest air of the season, more snow, high winds, a burst of warm weather, and then more cold.
When we get this type of extreme weather, the subject of climate change often comes up. I won’t get into a big discussion about it here but, while it’s difficult to tie these individual events directly to climate change, computer models do forecast more of these extreme events in a climate-changed world.
A wind chill advisory is posted for much of the area for late Thursday and Friday. The exceptions are the South Shore and Cape Cod, where it will still be cold, but wind chills won’t reach advisory-level criteria, staying above 15 below zero. Wind chills in the advisory area during this time could reach as low as 24 below zero during some of the highest wind gusts. At wind chills at that level (which we don’t see often around here), you you can get frostbite easily on exposed flesh, like your face.
Thursday night, readings will reach zero or a bit below well inland and will reach single numbers along the coast. That wind will really bring a bite to the air.
The wind may gust over 45 miles per hour and even reach 60 miles per hour. This can cause power outages from tree damage. The National Weather Service has issued a High Wind Warning for late Thursday night and early Friday.
Friday will be the coldest day since last February. Temperatures will struggle into the teens at the coast and remain in the single numbers in the foothills and mountains. This is cold, and this is early for this type of cold.
Warmer air will start to move north Friday night and Saturday. As it hits all the arctic air, it will be lifted over it, form clouds and, eventually, snow. This won’t be a big storm, but if you are planning on heading out Saturday, expect slow going on the roads.
Eventually the warm air will win, and the snow will transition to rain with a period of mixed precipitation and freezing rain in between. Ski areas will also see a change, but not enough rain to damage the conditions too much.
Sunday will be mild and wet, especially in the morning. Later in the day, a cold front will sweep back in the arctic air. Highs wil return to below average levels to start next week, but turn milder as we head toward Christmas.
I will be updating the forecast on Twitter @growingwisdom.