Air Masses, the Polar Jet Stream and Orographic Blocking

Mayo Village's weather is influenced by both arctic and polar fronting. The polar front is the boundary between the cold, polar air masses and warm tropical air masses.  As the temperature gradient between these air masses increases so does the potential for cyclogenesis. The arctic front, like the polar front, is dependent on temperature gradients between air masses. Arctic fronting typically produces precipitation in the form of snow. The Arctic front effects Mayo Village the most during spring and autumn by enhancing cloudiness.

Graphic Source: Air Masses. National Weather Service JetStream-Online School for Weather. NOAA. Updated: 2010 January 5. Accessed: 2011 October 22. http://www.srh.noaa.gov/jetstream/synoptic/airmass.htm

http://www.packyabags.com/canada/rubyrange/14daywinter.htm 

Mayo Village is located above polar latitudinal delineation of 60° N. The weather in this area is primarily induced by the continental polar air mass stimulated by radiational cooling. These air masses originate from the snow covered interior of Canada and effects on this province are cold, dry weather motivating stable atmospheric conditions. The cold front boundary strengthens and migrates south in the winter, weakening and migrating north in the summer.  Continental tropical air never quite makes it up to Mayo except during particular decadal oscillations, in which weak occlusion during the summertime can occur. Weak, cold type occlusion occurs in the summertime if mP air surpasses the coastal range.  

In the winter, the cold airs mass freezes the ground and cools the overlying air column up to 1 km, condensing moisture in the air onto the snow surface. With coldest temperatures located near the surface strong temperature inversion occurs and there is little mixing of the air column. These conditions are unfavorable for precipitation, and, what little moisture that does come from the atmosphere condenses as snow. This cold, dry air mass travels south easterly into North America becoming unstable at lower layers, eventually warming and  gaining moisture. 

Graphic Source: Air Masses and Fronts. Firemodels.org. Accessed: 2011 October 22. http://www.firemodels.org/downloads/.../pms_425_Fire_Wx_ch_08.pdf

In the summer increased solar radiation results in a relatively little surface cooling, weakly enhancing the temperature of air column near the ground. Results are relatively unstable conditions in the lower layers of air column. Dry conditions of the ground surface up to a high altitude of the air column would  tend to result in lack of cloudiness or precipitation, but as observed in the graphic below, this is not the case in Mayo.

Graphic Source: Air Masses and Fronts. Firemodels.org. Accessed: 2011 October 22. http://www.firemodels.org/downloads/.../pms_425_Fire_Wx_ch_08.pdf

Mayo Village, surrounded by water in various forms, observes enhanced precipitation and weak cyclonic activity in the summer. The increased sunlight and melting of semi permanent ground allows Mayo to thrive with vegetation that escalates moisture content of the air through the process of transpiration and evaporation from the water bodies that surround the area; increasing precipitation and cloudiness. 
Graphic Source: Water Cycle. 2011. Yukon Water. Government of Yukon. Last Updated: 2011 MAY 5. Accessed: 2011 OCT 22.

Here are the weather maps (water vapor, wind direction, water saturation, etc) for Mayo Village for October 29 2011. Illustrated is current jet stream location and orographic blocking on southwestern border of Yukon. The polar jet stream migrates south during the winter and north during the summer. Mayo Village rarely observes summer temperatures higher than 80 F.

Graphics Source: Satellite Images (data courtesy of NOAA). Weather Office, Canada. Updated: 2011 OCT 12. Accessed: 2011 OCT 29. http://www.weatheroffice.gc.ca/satellite/index_e.html

The northern tip of the Rocky Mountain/Pacific Cordillera and the St Elias Mountain Range lie to the southwest of Mayo Village along the Yukon/Alaska border. The range prevents the moist maritime polar air from intruding Mayo Village via orographic blocking. The boundary between the cP (darker blue) and mP (turquoise blue) air masses can be observed to the southwest of the mountain ranges. 

Graphic Source: What is an air mass? 2011. Wheatherquestions.com /Weatherstreet.com. Accessed: 2011 OCT 31. http://www.weatherquestions.com/What_is_an_air_mass.htm

Adiabatically heated air rushes down the lee side of the St Elias Mtn Range, enhancing dry conditions  experince in Mayo Village during wintertime. 

Chinook Wind. Wikipedia, the free encyclopedia. Updated: 2011 OCT 8. Accessed: 2011 OCT 31.  http://en.wikipedia.org/wiki/Chinook_wind

Graphic Source: St. Elias Mountains, Kluane National Park, Yukon Territory, Canada. Radius/SuperStock. Accessed: 2011 OCT 31. http://www.superstock.com/stock-photography/Saint+Elias+Mountains

Polar vorticity consists of persistent large scale cyclonic activity in the mid- troposphere to shallow stratosphere, centered in polar regions of North and South Hemisphere. The Arctic Vortex, the northern polar vortex,  disturbs weather patterns particularly in the eastern part of North America, and, only skims the edge of the Yukon. Therefore the Arctic Vortex has relatively weak effects on weather in Mayo. 

Tyrsina R. 10 Differences Between the North and South Poles. Science and Nature, Ultimate Listverse. 2011 JUN 19. Accessed: 2011 OCT 31 . http://listverse.com/2011/06/19/10-differences-between-the-north-and-south-poles/

Additional Sources:

Arctic Climatology and Meteorology Education Center.  National Snow and Ice Data Center.  Accessed: 2011 OCT 29. http://nsidc.org/arcticmet/

Lutgens, F.K. Tarbuck E.J. 2010. The Atmosphere: An Introduction to Meteorology.  Pearson Education. Chapters: 4, 6, 7, 9.