Our weather over the next several days looks quite complicated and will present a lot of forecasting challenges. Today is simply a sunny, cold day with temperatures below long-term averages, right around 30 degrees. We should be closer to the upper 30s this time of the year.
Overnight clouds will move in, but temperatures will fall down to the teens to around 20 degrees, with the warmest temperatures over Cape Cod.
On Friday, snow will break out across the area during the morning or early afternoon. This isn't going to turn into a big snowstorm, but there will be snow falling and the roads will be cold and slippery. I'm looking for coating to an inch or two of snow around Boston but a little more to the north.
Friday night, the snow will transition over to rain and freezing rain as warmer air comes in at high levels of the atmosphere with a cold ground.
This means up as the precipitation falls, it will melt from snow to rain but then refreeze once it hits the ground. The greatest likelihood of a significant impact from the freezing rain would be west of I-495 and north into southern New Hampshire, but even in the Route 128 belt there could be some accumulating glaze for a few hours Friday night.
This situation will need to be watched closely, for if the freezing rain lasts for a long time and the ice builds up to more than half an inch, you can see power outages.
On Saturday everything should transition over to rain with the freezing rain lingering longest over northern Worcester and Franklin counties. There will be a break in the action for Saturday night and Sunday before the next storm system hits us on Sunday night and Monday.
This Christmas storm is likely to be mainly in the form of snow or rain changing to snow. Since the storm is four days away, the amount of snow is still very questionable. The storm could be significant depending on exactly where it develops so stay tuned to later forecasts.
You can follow my updates here and on Twitter @growingwisdom.
Thursday: Sunshine and a few clouds, cold. Highs 25-30.
Thursday Night: Clouding up and cold lows 15-20.
Friday: Cloudy, snow or mixed precipitation before changing to freezing rain or coastal rain late at night. Freezing rain could be significant inland. Highs 32-40.
Saturday: Early icing north and west, then showers. Afternoon readings 32-42. Warmest over Cape Cod, coldest north and west of I-495.
Sunday: Partly cloudy and seasonable. Highs 35-40.
Christmas: Any snow ending in the morning. Highs 33-38