Chilly blanket

Posted at 4:09 PM on December 3, 2008 by Paul Huttner

A light dusting of fresh snow graces the Huttner Weather Lab at sunset.

It's called albedo. "Big Al" plays a huge role in our temperatures this time of year.
Albedo is best described as the amount of reflectivity of sunlight on different surfaces on earth.

Your asphalt driveway may absorb over 90% of the sun's energy. Bare ground in winter may absorb as much as 80% and re-radiate some of that energy to warm the air near the ground.

Effect of snow cover

But fresh snow cover reflects as much as 80% to 90% of all incoming solar radiation back into space.

albedo of various surfaces

That's why it will be much colder in Lakeville tonight than in the Twin Cities where some areas still have bare ground. We can see big temperature variations on nights like this where snow cover is highly variable.

The fresh blanket of 2" to 5" of snow south of the metro will make for cooler nights and days this week.

Twin Cities NWS snowfall amounts

At least the kids in Vermillion can go sliding!

PH

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