The Forecast Calls for Weather

As I look outside my window, I'm starting to see red, orange, yellow, mixed in with all the green of the deciduous trees. This is a sure sign that fall is upon us and winter is not too far off. With my sights now fixed on the coming winter, I've started wondering what this snow season will bring. This year, instead of sticking to the usual routine of flushing ice cubes down the toilet, or wearing my PJs inside out, I've decided to turn to science — perhaps our political leaders will take note and do the same when drafting policy — I have taken a look at the El Niño Southern Oscillation (ENSO) climate pattern to gain some insight.

img_2055.jpgCold temps and low pressure, in this case caused by orographic lift, usually leads to snow.

ENSO is a quasi-periodic climate pattern which is characterized by variations of the surface of the tropical eastern Pacific Ocean and air surface pressure in the western Pacific. The mechanisms that cause these oscillations are still not fully understood, however, what is understood is that the warm oceanic phase, El Niño, accompanies high air surface pressure in the west Pacific, while the cold phase, La Niña, accompanies low air surface pressure in the west Pacific1. Any of you who have ever taken a Avi course will probably realize at this point that the combination of low pressure and cold temperatures are the ideal conditions for snow. Which would occur on the western coast of North America during a La Niña phase. Armed with a better understanding of ENSO, I now have something specific to pray Ullr for.

In June, the National Oceanographic and Atmospheric Administration Climate Prediction Center issued its monthly discussion on ENSO. One detail that caught my attention was the phrase "La Niña Watch", which gave me hope that Ullr may actually have heard my prayers. I decided to take it further and read the full ENSO discussion to learn more, and struck gold in the third paragraph of the report:

The transition into the Northern Hemisphere Fall means that La NiƱa will begin to exert an increasing influence on the weather and climate of the United States. These impacts include an enhanced chance of above-average precipitation in the Pacific Northwest

This discussion certainly fits with the observed mechanisms of the ENSO. The fact that we're entering a La Niña period also brings hope for a snowy winter. In Canada, La Niña will generally cause a cooler, snowier, winter. The last time we experienced a La Niña winter, was in 2007/2008 when near record-breaking amounts of snow were recorded in eastern Canada2. I'm hoping that I'll be similarly blessed this winter.

Similarly, a chance for above-average precipitation in the Pacific Northwest means that this winter will likely bring a lot of snow in that region. Especially in mountainous regions where orographic lift has a significant influence on temperature and precipitation. This bodes well for my upcoming trip to Whistler in late December. It also brings promise for a good ender at at this year's Tailgate Alaska; I'm already looking forward to living on the pass temporarily this spring.

I'm so stoked on the winter already that I've taken to wearing my snowboard pants around the house. It seems ludicrous but it might also be prudent, especially if this La Niña winter is anything like the winter of 2007/2008. So grab your toques, and hope for a good one.

Winter Matters Bubble

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