Air Masses in Nepal

Wind!



http://www.kuoni.co.uk/en/holiday/asia/nepal/pages/default.aspx



http://www.phoolbari.com/tourism/aboutnepal.html















Kathmandu serves as a popular destination
 for mountaineers before they ascend into the high Himalayas!


In the northern hemisphere, latitudes between thirty and zero degrees are normally subject to the northeast trades that move from subtropical high pressure to equatorial low pressure.  However, Nepal is a special exception.  The Himalayas act as a great barrier against the cold air that sweeps across Asia.  Arcing gently east-west across the region, the mountains shield Kathmandu from these air masses (cP and cA), resulting in the city's surprisingly temperate climate.  Kathmandu's climate comes as a shock to some because it seems to defy that which the region is known for: high altitude adventure. 



The temperatures of the city itself are quite moderate. 
Here, Kathmandu's cricket team enjoys a spring day



This satellite image shows how the Himalayas protect south Asia from cold, NE air masses.  Clouds are clustered near the top of the image, but cease abruptly near the base of the mountain range. 



Nepal is affected primarily by maritime tropical wind currents from the Indian Ocean and is also subject to an annual summer monsoon.  Air masses sweep to the northwest over the Indian Ocean where they become warm and moist before circling towards India, generating precipitation during the months of June-August.

This map illustrates the precipitation and wind patterns experienced during south Asia's summer monsoon season.  Kathmandu is located just below the dashed line at 27°42′N 85°20′E.  It's no coincidence that air masses suddenly change direction when they come to the dashed line--the line follows the arc of the Himalayas.
http://www.theresilientearth.com/?q=content/monsoons-megadroughts

Kathmandu is not affected by mid-latitude cyclones, as illustrated below.

This image shows the typical paths of mid-latitude cyclones (black arrows) and hurricane tracks (green).  Kathmandu is a  mid-latitude cyclone will not develop over this region because the Himalayas prevent tropical air masses from merging with the polar air masses that dominate Asia.
http://www.physicalgeography.net/fundamentals/7s.html