Our workweek is going to end with sunshine and seasonably cold temperatures, but the weekend will turn snowy for the first time this season with widespread accumulation.

A storm system will move up the coastline Saturday and bring precipitation to the area starting by late morning or early afternoon that will last through much of the night. Expect the heaviest snowfall from roughly 2 p.m. Saturday to 3 a.m. Sunday. The timing could shift a few hours in either direction so check back later Friday or Saturday morning for a fresh look at the forecast.

This is generally a 3-6 inch snowfall with a few exceptions. (Dave Epstein/WBUR)

This is generally will be a 3- to 6-inch snowfall with a few exceptions. (Dave Epstein/WBUR)

The moisture fueling this storm is actually the same moisture that brought early snow to Texas Thursday. Some energy from Canada will merge with that moisture off the Maine coast Saturday to form our storm. This won’t be a blockbuster snowfall, but a few places may go above the predicted 3- to 6-inch range.

The southern branch of the jet stream will bring moisture to Maine Saturday. COD Weather

Moisture is already streaming north from the southern jet stream early Friday (COD Weather)

RAIN VS. SNOW

The other forecasting challenge with the storm is the rain/snow line. The outer islands and many of the peninsulas east of Portland will likely get at least a mix with rain.  The outer tip of Cape Elizabeth will also likely end up with some rain, although there could be a few inches of slush.

South of Portland along the immediate shore roads, the precipitation may flip back and forth and there will be lesser amounts there as well. If the storm jogs a little west or east then the rain could push inland a little more or the snow could push toward the coast a little more so those of you in that area should be aware the forecast could change the most for you.  

Temperatures are forecast to go above freezing Sunday. WeatherBell

You may have noticed that some of the trees – especially Japanese maples – continue to hold onto their leaves. That’s because a cold snap iwhile the plants were still growing in November stopped the abscission process and left the leaves on these trees. Saturday’s heavy, wet snow could add a lot of weight to these trees like these, so it wouldn’t be a bad idea – if you can – to gently shake the snow off the limbs during the storm to prevent breakage.

NOT A HUGE SNOWSTORM

This isn’t the type of storm that’s going to shut down the Portland Jetport or create long-term travel issues. This is a typical December moderate snowstorm. Just leave yourself extra time to get to where you’re going because roads will be slick much of the afternoon and evening Saturday.

After some lighter snow showers, Sunday will see clearing skies and cold temperatures.  Down East Maine will hold onto the snow and rain longer Sunday and there is a winter storm watch posted  for Houlton and Millinocket.

MORE SNOW AND COLD

There is another storm we need to watch for later Tuesday and Wednesday.  However it materializes – whether a few snow or rain showers or a more impactful storm – much colder arctic air will arrive at the end of next week and temperatures will fall well below normal for several days.

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