Updraft: December 12, 2007 Archive

Hoarfrosty morning

Posted at 7:00 AM on December 12, 2007 by Paul Huttner (4 Comments)

It’s a winter wonderland outside the Weather Lab this morning. The trees are frocked in white, looking like an early Christmas present today.

It's called "hoarfrost." It happens when ice crystals are deposited directly on surfaces like trees and fences that are exposed to the humid sub-freezing air.

Hoarfrost defined

Hoarfrost photo

Conditions were perfect overnight with ice fog around the metro, and as you wake this morning take a look out and enjoy the beautiful Currier and Ives display around the metro.

PH

Arctic Sea: Ice free summers by 2012?

Posted at 8:32 AM on December 12, 2007 by Paul Huttner

Arctic Sea ice hits new record low

Pendulum poised to swing?

Posted at 1:16 PM on December 12, 2007 by Craig Edwards

Well, is the pendulum about to swing? Currently, we find ourselves ten degrees below normal for the first 11 days of December with another surge of chilly air arriving for the start of the weekend! But, if you have any confidence in the longer range outlook from the National Weather Service, we may be on the brink of a transition to milder air over the northern Plains and the Great Lakes.

Eight to fourteen day outlook

With a snow drought in December of 2006 we began the month some eight degrees below normal in the Twin Cities. By month’s end, minus a decent snow cover, the record book documented a departure from the 30 year average of more than ten degrees on the plus side of normal. Quite a turn around as the daylight continued to shorten.

Less than a week from now we may find ourselves playing host to temperatures above the 30 year average. But this time the return of milder air will have to make its way over a layer of snow. Weather watchers have learned that milder air meandering over a coating of icy snow favors the formation of a damp dense fog.

So while the outlook tilts the odds towards above normal temperatures over much of the nation, be cautious about feeling the warmth. A gray misty day with a high of 30 may go down as warmer than normal, but not necessarily be a reason to celebrate.
CE