In spite many of us getting to spend a lot of time outside in the warmth over Christmas, it’s time for a reality check, snow is on the way.

There are basically two things you need for snow, moisture and cold. Tuesday morning we will have each of those in place. My forecast is predicated on the cold hanging around long enough to keep the precipitation in the form of snow, for most of the storm.

When Does The Snow Arrive?
Tuesday is snow day with the snow arriving in the pre-dawn hours and continuing for much of the day. The snow could be heavy at times and I expect the National Weather Service folks in Gray to issue winter storm watches later today. This means there is the possibility some areas could reach and exceed 6 inches of snow. Since there isn’t any school, we don’t have to worry about that aspect of the forecast.

Will the snow be fluffy or wet?
The snow will be moderately dry, but trending heavier during the storm, especially south of Portland and along the coast. As temperatures get closer to freezing that’s when the snow becomes heavier. Last winter nearly all of our storms had snow which was incredibly light and fluffy. You should expect more storms with snow that is on the heavier side, especially at the coast, this winter.

How Much Snow?
This is always the million dollar question. There are three maps below to help you know how much snow is coming. The first is my map and my prediction. I followed that by a map produced by NOAA. Their map has specific numbers due to the way it’s rendered, not ranges.

Finally, there is a map of probability. This map shows the odd of seeing 4 inches of snow or more. Notice the odds decrease rapidly over extreme southern Maine.

Could Accumulation Change?
There are still several model runs today and Monday. As each new bit of information arrives, I will modify the forecast. The exact strength and speed of the storm will ultimately determine our snow totals. This doesn’t have the potential to turn into a major snowstorm like what we saw last February.

How Will the Recent Warm Weather Affect The Storm?
Soil temperatures are still in the lower 40s and while they will cool down Monday, the ground won’t be frozen. Roads are also relatively warm. This means some of the snow will melt from the bottom up. Anytime temperatures go above freezing the rest of the week we will also lose some of the snow. Portland typically receives its permanent snow cover for the winter right about now, so it’s not out of the question if enough snow fell you won’t see bare ground for a while.

Ski areas should keep nearly all the new snow which is great news for those of you at the slops this vacation week.

I’ll update the forecast here and on Twitter @growingwisdom.

Colder Pattern
In the years since records have been kept around southern New England, we have never had a December this warm. January is the coldest month of the year and even a milder than average month is still cold. I expect January to average either slightly above or slightly below average, but not be exceptionally cold or warm.

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