We finally had some winter weather on the weekend dropping about 4 inches of lovely, fluffy snow. Everything looks lovely today, all white and pristine. Unfortunately it does not look like it is going to last as they are predicting a return to unusually warm temperatures again this week.
So far this winter we’ve had only 10 days where the high for the day remained below freezing. A far cry from the typical Canadian winter. So what is happening to winter? Apparently the cause is something called The Arctic Oscillation. This interesting weather pattern dictates how much arctic air leaves the pole region and is driven down into the middle portion of the northern hemisphere. When positive, which it is now, low surface pressure in the polar region and higher pressure below means that the jet stream remains strong and relatively high in latitude, keeping cold Arctic air trapped in the polar region. When negative, strong pressure in the Arctic drives the jet stream lower, hence our normally cold winters.
Last winter the Arctic Oscillation was negative, driving down temperatures and increasing snow cover, this year it has been positive (no I’m not referring to the upside of not having to shovel). All I know is I hope it stays ‘positive’ for spring.