The upcoming cold has been advertised almost as much as a snowstorm and you may wonder what the big deal is, but if you step outside from late Saturday afternoon through Sunday you’ll know why we’ve all been talking about it for the past week.

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The good news about the arctic blast is it won’t last very long.  By Monday afternoon temperatures will feel over 50 degrees milder than just 36 hours earlier.  That turnaround will be remarkable in itself.

The pool of cold air is like a big mass of dense molasses pushing its way southward on a very strong wind.  If you have plans outside today the best time to do this will be before noon along the coast, and a few hours earlier across the far western areas of Maine.

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The map below shows temperatures early this afternoon.  This is when the wind will be starting to howl.  As the arctic front pushes through, you’ll hear and feel a strong gust of wind.  At this point temperatures will start to plummet quickly, losing 10 degrees in under an hour and a fully 20 degrees between early afternoon and mid evening.

Late Afternoon Temperatures-Credit:WeatherBell Analytics

Late Afternoon Temperatures-Credit:WeatherBell Analytics

Wind chill becomes a player in the forecast along the coastline as the sun goes down, but will already be at dangerous levels through the mountains.  The graphic below really tells the story of the wind chill  and you can almost feel it pushing eastward.

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Winds will gust over 30 miles per hour and there could be a scattered power outage from these winds.  The wind isn’t strong enough to create widespread problems, but there’s often a tree limb weakened from previous storms that ends up falling.

There are wind chill warnings and advisories for Saturday evening and Sunday morning.   The combination of wind and cold will make frost bite on exposed skin likely if you are outside in as little as 15 minutes in the mountain areas to around 30 minutes along the immediate coastline.

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Remember, this is on exposed skin.  If you dress properly with a face mask, hat and gloves, you can still go outside.  It may seem obvious to most, but running in this kind of cold can be harmful to your lungs.  These organs require warm moist air.  Breath through your nose, not your mouth to allow the air to warm before it ends up in your lungs.

Temperatures Sunday morning even without the wind will be cold.  The record in Portland is 17 below zero and a forecasted 3 or 4 below means the record will stand. However, this will be one of the top 10 coldest Valentine’s days on record.

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Cold air is very dense and dry.  As a matter of fact, if you heat your house into the 60s the relative humidity of the air will be 2 to 4 percent tonight and tomorrow.  This is going to cause chapped lips, lots of static and a generally dry feeling.  This is a good time to have the humidifier going full blast.

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Cold air is also heavier and denser than warm and moist air.  While this may seem counter intuitive it’s true.  Check out the explanation from Hanby’s Hints.  If you are a math person this can be a fun exercise.  It’s actually a good problem for school kids as well.

Dry Air Is Heavier Than Moist Air-Credit:theWeatherprediction.com

Dry Air Is Heavier Than Moist Air-Credit:theWeatherprediction.com Photo by Elise Klysa