Tuesday, January 3, 2012

Arctic Oscillation - Positive Phase Means Warmer Weather

Amazing Pictures From The North Shore
Thanks to Paul Sundberg for these great pictures from the always picturesque North Shore. Paul, you continue to amaze me with the quality of your work, capturing Mother Nature at her best!

Grand Marais Lighthouse - Paul Sundberg

Sawtooth Mountain Sunset - Paul Sundberg
 

With temperatures as cold as they are to start our Tuesday, you might think it's a little premature to talk about a January thaw. Believe it or not, temperatures aloft are warming, which by the end of the week, could have temperatures near the ground around 40F, if not into the low 40s Thursday and Friday.
     Some winter we're having, don't you think? It's almost a complete 180 from last winter when we were setting snow records. This year, our season snow tally is a measly 10", nearly a foot behind normal. Our greatest snow depth so far this year was 4" back in early December. In contrast, the winter of 2010-2011 boasted over 44" of snow through today's date with the greatest snow depth in Dec. at a whopping 19". It was a winter wonderland, white gold sent winter sporting sales through the roof.
     2011's slow start to winter continues into early 2012 and I still see no major winter storms or long duration cold snaps through the middle of January. Of course, the cold and snow go hand in hand. With the lack of a deep snow pack, it's harder to keep temperatures colder. Even the Climate Prediction Center's temp outlook keep us warmer than normal through the end of January...

Thin Ice Still Threatens Area Lakes
On my way home from the WeatherNation studios yesterday, I had to stop and take a picture of Independence Lake when I noticed that it still had some open water! I couldn't believe it when I saw ice houses (not pictured) on a lake that still had open water... Good grief!

 DNR Officials Still Warning of THIN ICE!
Here's a nice article from  HERÓN MÁRQUEZ ESTRADA from the StarTribune. Read the story HERE:
"On many lakes where ice-fishing shacks usually amount to subdivisions by this time, it’s been a different scene this winter. Even where shacks are out on lakes, their numbers have been reduced by those that have fallen through the ice."

Read The DNR Ice Safety Guidelines HERE 




Snow From Space
Icy sunshine on Monday revealed the wintry landscape across Minnesota. Snowfall over the weekend wasn't all that impressive, but it was enough to be seen from space nearly 23,000 miles high! Even this little bit of snow helps to chill temperatures even more during the daytime and nighttime hours. Monday morning to Tuesday morning temperatures were some of the coldest readings we've seen since the 9th & 10th of December. In fact, the daytime high temperature on Monday was below average for the first time since December 16th. We were on a 16 consecutive day run of above average temperatures until yesterday.
 
Why Has It Been So Warm?
One potential reason could the the 'Positive Phase' Arctic Oscillation that we're in right now.
The information below is from NOAA - I urge you to read to read it, it's very interesting!

"One of the biggest influences on U.S. winter climate is the Arctic Oscillation, a natural seesawing of atmospheric pressure between the Arctic and the mid-latitudes of the North Pacific and North Atlantic Oceans. Because it isn’t predictable very far in advance, climate forecasters often describe the Arctic Oscillation as the “wild card” of the winter forecast. So far this winter, the Arctic Oscillation has been in its positive phase, playing the card that favors a milder winter in the eastern United States."

"During the positive phase of the Arctic Oscillation, on the other hand, air pressure and wind patterns tend to drive winter storms on more northerly tracks. The eastern United States and Europe tend to have milder than normal temperatures, such as we have experienced this year to date, while Greenland and easternmost Canada are even colder than they normally are during the winter."
"In fall and winter of 2010, the Arctic Oscillation was persistently and often strongly negative—the lowest it has been in the last 60 years, in fact. During the negative phase of the pattern, air pressure and polar jet stream patterns tend to draw Arctic air down into the eastern United States. With this cold air in place, passing storms are more likely to generate heavy snow. A “return flow” of milder air from the mid-latitudes warms western Greenland and eastern Canada. Across the Atlantic, the polar jet stream tends to dip farther south than usual over Europe, favoring chillier than usual winters."

Changing Air Masses
Take a look at the air masses and how different they are from Monday into Thursday.

Monday
Some of the coldest air we've seen since December 9th & 10th, nearly a month ago.

Thursday
If we can melt most of the snow by Thursday and Friday, there's a chance that 50s could pop up in the southwestern corner of the state.

Thanks for checking in, have a great rest of your week. 
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Meteorologist Todd Nelson