It all depends on the snow cover

Adam blogged about this earlier today so I thought I would talk more about that and albedo.

During the day bare ground (no snowcover) absorbs the heat and energy of the sun. It then releases a little of that heat during the night, keeping temperatures warmer. (It is a rare event in Northern Illinois to get temperatures to fall below zero without snow on the ground.)

So, what's this albedo business? Albedo is basically the same thing as reflectivity. Because snow is white, it reflects most of the sun's energy and thus has a high albedo. Since there's no heat absorbed, there's none to give back during the nighttime hours.

If we get snow Thursday and it piles up a few inches or more, we'll see temperatures fall like a rock. Below zero high temperatures are possible! Blame it on albedo?