Wednesday, January 4, 2012

Lack of snow cover really helps our temperatures

The weird and mild winter weather will continue for the next week or so as temperatures are expected to warm right back up into the 40s and even possibly the 50s to our south and west later this week.

We've talked a little about the jet stream and how the positive NAO has had an affect on it so far this year.  Now let's talk about albedo.  Albedo is the amount of solar energy that is reflected from earth back out to space.  Snow and ice have a higher albedo while water, forest and land have a lower albedo.  When the ground is covered with snow roughly 85% of the sun's rays (shortwave energy) is reflected back to space keeping the surrounding atmosphere cool.  When there is very little or no snow on the ground most of the shortwave energy is absorbed by the earth, therefore heating the surrounding air mass.

The fact that we're lacking any sort of snow on the ground combined with our wind source originating from places that have either very little or no snow is what's helping keep temperatures well above average.  Highs the next couple of days will warm into the middle and possibly upper 40s by the end of this week.  This is the time of year when we start to typically see, climatologically speaking, our coldest temperatures.   

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