Whistler British Columbia is affected mainly by three air masses. These are the maritime polar air mass (mP), arctic air mass (A), and continental polar air mass (cP). To a lesser extent, the maritime tropical air mass (mT) will move further north and affect Whistler's climate. Maritime air masses tend to have more influence in British Columbia during the winter months than in the summer.
Air masses and Polar front affecting Whistler BC
Image from: National Weather Service. N.p., n.d. Web. 13 Apr. 2014.
The cities location at about 50 degrees north means it does not experience many mid latitude cyclones. It is just above the polar front, so although plenty of these cyclones develop around the area they move southwest before any impact is created. When there is an affect from these cyclones, they create occluded fronts. Warm occlusions in the summer, and cold occlusions during the winter season.
Whistler falls into a long wave ridge which typically sees the arrival of high pressure systems that rotate clockwise. This is caused by convergence in the troposphere and divergence at the surface making air parcels sink. With low pressure systems surrounding it, warm occluded fronts form that bring precipitation to the region.
The area is currently experiencing an occluded front that is viewable in the image below moving down towards the pacific northwest of the United States in the following days. This front has brought and should continue to bring small chances of light precipitation through Wednesday April 16.
Weather forecast map for Canada April 15 and 16
Image from: "Weather at a Glance." Environment Canada. N.p., n.d. Web. 14 Apr. 2014.
A large factor in Whistler's weather and climate lies in its topography. The city is located centrally in the Canadian Rocky Mountains which run north to south. The orographic feature lifts the air masses that approach it, creating clouds. With the maritime polar air mass constantly moving westward towards the mountains, a large amount of vapor is lifted. This is a key component in the vast amounts of snowfall the area receives.
Every so often a deep column of moisture known as the pineapple express moves northwest from the pacific ocean around Hawaii up towards the west coast of North America. The maritime tropical air mass and a branch of the polar jetstream carries this vapor concentrated air inland causing massive amounts of precipitation. Below is an image of the pineapple express reaching the mainland in January of 2009. This "atmospheric river" reached far enough North to affect Whistler and brought generous snowfall.
A large factor in Whistler's weather and climate lies in its topography. The city is located centrally in the Canadian Rocky Mountains which run north to south. The orographic feature lifts the air masses that approach it, creating clouds. With the maritime polar air mass constantly moving westward towards the mountains, a large amount of vapor is lifted. This is a key component in the vast amounts of snowfall the area receives.
Every so often a deep column of moisture known as the pineapple express moves northwest from the pacific ocean around Hawaii up towards the west coast of North America. The maritime tropical air mass and a branch of the polar jetstream carries this vapor concentrated air inland causing massive amounts of precipitation. Below is an image of the pineapple express reaching the mainland in January of 2009. This "atmospheric river" reached far enough North to affect Whistler and brought generous snowfall.
Pineapple Express moving far enough north to affect Whistler BC
Image from: "COPE Laboratory - Research Projects." COPElab School of Resource and Environmental Management RSS. N.p., n.d. Web. 13 Apr. 2014.
References:
"Air Flow Through Two Wintertime Mid-Latitude Cyclones Interacting with Mountains." Air Flow Through Two Wintertime Mid-Latitude Cyclones Interacting with Mountains. N.p., n.d. Web. 13 Apr. 2014. <http://adsabs.harvard.edu/abs/2011AGUFM.A51C..05B>.
"COPE Laboratory - Research Projects." COPElab School of Resource and Environmental Management RSS. N.p., n.d. Web. 13 Apr. 2014. <http://www.rem.sfu.ca/COPElab/research/research-projects/>.
National Weather Service. N.p., n.d. Web. 13 Apr. 2014. <http://www.srh.weather.gov/srh/jetstream/synoptic/images/airmasses.gif>.
"THE PINEAPPLE EXPRESS." THE PINEAPPLE EXPRESS. N.p., n.d. Web. 14 Apr. 2014. <http://www.weather.com/blog/weather/8_10838.html>.
"Pineapple Express." Wikipedia. Wikimedia Foundation, 14 Apr. 2014. Web. 14 Apr. 2014. <http://en.wikipedia.org/wiki/Pineapple_Express>.
"Weather and Climate of British Columbia, Canada." Weather and Climate of British Columbia Canada. N.p., n.d. Web. 13 Apr. 2014. <http://climatebc.wordpress.com/>.
"Weather at a Glance." Environment Canada. N.p., n.d. Web. 14 Apr. 2014. <http://weather.gc.ca/jet_stream/index_e.html>.
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