Why is the center of the country colder in the winter

Question

Every winter when cold air comes down from canada, it always hits minnesota and north dakota with full force, and even extends down into nothern texas. The eastern half of the country is cold, but nowhere near as cold as the central part of the country. Why does the frigid air always enter in the center of the country and not the eastern part.

Answer 1

Actually, the jet stream is more of a response mechanism than a causal one.  The center of the country is more favored for the initial surges of arctic air for a couple of reasons.  One, the polar vortex (a large and persistent mid and upper level low pressure area) tends to set up in the vicinity of Hudson Bay in Canada.  The counter-clockwise rotation around this low allows for surges of cold arctic air to move southward across central Canada into the center of the U.S. before sliding eastward.  There is also a secondary process that tends to pull the cold surface air masses southward initially.  The slope of the central U.S. is such that the terrain gets gradually higher as you go west over the plains, before abruptly rising at the Rocky Mountain chain.  The surface highs associated with the very cold air rotate clockwise, thus the cold air from them is lifted up along the higher terrain which cools the air even further.  This cooling causes the surface high to actually move in the direction of cooling, thus they hang close to the Rocky Mountain chain for a while before finally breaking eastward.  This effect also tends to cause the cold outbreaks to drop initially into the central U.S.

Answer 2

It's just the way mother nature wants it to happen. Plus the eastern part of the US, some of it is on the water so wouldn't that make it warmer? Plus in states like VT and CT, it does get pretty cold up there. NY too. But not as cold as Minnesota and North Dakota. That's just what Mother Nature wanted.

Answer 3

It has to do with the way the jet stream runs and it dips down in the middle of the country and usually pulls up before the Eastern coast, sometimes the jet stream dips a little south eastern and New England gets just as cold.