Posted at 8:29 AM on January 26, 2011
by Paul Huttner
Filed under: Climate
November 13th. Mark it down as the day winter began in Minnesota. The season's first winter storm blasted Minnesota with a snowy swath of 8"+ from Fairmont to the Twin Cities to Duluth.
Just 3 days earlier we basked under sunny skies and set a record high of 68 degrees in the Twin Cities. That run of Indian Summer November 7th-10th capped off the 3rd latest 4 day stretch of highs in the 60s on record in the metro. Remember how GREAT that felt?
Fast forward to today, January 26, 2011. 74 days later a series of at least 9 significant snow events (and several minor dustings) have laid down a total of 55.4" of metro snow...with similar hefty totals around much of the state. We are now near the overall season average of 55.9" at MSP Airport...a number we may reach this week.
Consistent cold has also been a feature in the past 2 and-a-half months. Since November 13th we have only reached 40 degrees in the metro 3 times. The Twin Cities has not climbed above freezing (or thawing!) for 27 days... since December 30th, when the mercury mercifully soared to an ice dam busting, rain soaked 42 degrees!
Even by Minnesota standards, this has been a rigorous, character building, persistent winter of cold and snow.
Warmer Arctic to blame?
The winter of 2010-'11 is unusual in that it's been unseasonably warm in Greenland and inside the Arctic regions of northeast Canada, even as persistent cold and snow is being driven south into Europe and the USA.
Climate scientists have indentified several regional patterns or "oscillations" that have an impact on seasonal climate. There's the North Atlantic Oscillation (NAO), the Pacific-North American Oscillation (PNA), The Pacific Decadal Oscillation (PDO), and the more famous El Nino Southern Oscillation (ENSO) to name a few.
Each pattern affects different regions of the globe and operates on different time scales. These overlapping regional and global systems make it difficult to pinpoint seasonal pattern around the globe with say 80 or 90% certainty. That means any give winter can be different depending on which regional climate phase is dominant. It's difficult, if not impossible; say which happens first and what "drives" what...a little like the chicken & egg.
A more recent theory is that this upside down winter is driven (or "forced" as climate experts say) by unusually warm water in the usually frozen Arctic Ocean. ABC News filed this story Tuesday.
Pattern change ahead?
This winter has featured a persistent big "boss man" Polar Vortex over Hudson Bay. The upper low has kept Minnesota in northwest flow, dealing us arctic air masses for the past two months.
There are signs that may be about to change...a little. The GFS has hinted now for a few runs that the Hudson Bay Polar Vortex may shift slightly north over the next two weeks. That won't end winter anytime soon, but it should be enough to allow some milder Pacific air to slide over the Upper Midwest periodically in the next two weeks.
The first shot of relief comes this week, as temperatures may approach of hit the thawing point Thursday & Friday in southern Minnesota.
After another arctic shot next week, it looks like we could see a more extended thaw the first week of February. If the models verify, we may see temps above freezing somewhere in the Feb 3rd to 5th time frame.
Hang in there...our weather luck may be about to change for the better!