An air mass of the Pacific flows far north, infiltrates the Arctic, displaces the air mass of the Arctic, which flows south displacing the Temperate air mass over North America. Meanwhile, another Tropical air mass, originating in the Gulf of Mexico, flows north and encounters the errant Arctic air; the Tropical air flows over that colder, denser air, and, cooling as it rises, it can no longer hold the moister that it contains, which condensates as snow.
What subtle and far-off forces affect our lives. However we may seek to be of temperate nature, events that originate outside our hemisphere of influence will converge and precipitate their effects upon us. Our ability to hold steady our internal barometric pressure, no matter the external high or low pressure systems that we find ourselves immersed in, is of course the measure of how well we’ve weathered the storm.