What happens when a very cold, very dry air mass comes in contact with a very warm, very moist air mass?

Question

What happens when a very cold, very dry air mass comes in contact with a very warm, very moist air mass?

Answer 1

Babies are made.

Answer 2

You have a frontal system.  Typically the cold and dry airmass, being heavier and denser than the warm and humid airmass, will undercut and lift the warm and humid airmass.  If other factors are right, such as sufficient instability, you can get the formation of precipitation.  It does not always happen, as sometimes the colder air will simply push the warmer air away.  

Answer 3

Storm and winds.