| Summary: | as the very short term. Just as one year of weather in North Dakota can be quite different from another year, weather in North Dakota is also sometimes prone to tremendous changes hour by hour and even minute by minute. North Dakota's northern border is the 49th parallel. The southern border is approximately 45.9 degrees. This means the state is roughly halfway between the tropics and the North Pole. This middle latitudinal location is the place where warm air and cold air most often meet, resulting in a tighter north-south temperature gradient than is found closer to the tropics or the poles. Up in the air, 30,000 feet above North Dakota and paralleling this temperature gradient, is where the Polar Jet Stream is located. Storm systems form and move along the jet stream almost as if it were a sort of a storm freeway, undulating northward and southward but rarely straying far from North Dakota for long. This means North Dakota gets a lot of storms compared to most other places. North Dakota is approximately 1,200 miles from the Gulf of Mexico and 1,600 miles from the Yukon. And in between these completely different climate regimes, there is nothing more substantial than a few barbed wire fences to stop the wind from blowing around. Due to the flatness of the terrain and the resulting lack of surface friction, the Great Plains are a windy place. More than that, due to the great expanse of the plains in North America, North Dakota is a fantastic mixing area for different air masses. A stiff south wind can bring air from the coast of Texas to North Dakota in under three days. Likewise, air from the arctic regions of northern Canada can get to North Dakota very quickly. So when the wind changes direction in North Dakota, it can mean a complete change in the weather. This is why North Dakota is prone to such extreme temperature changes from one day to another. Weather coming to North Dakota from the west or southwest is usually quite dry. However, with the counter-clockwise rotation of air around the low pressure systems which frequent North Dakota, these weather systems are able to tap into subtropical air from the Gulf of Mexico with a south or southeast wind. East and northeast winds can be cool and damp or very cold and dry, depending on what sort of weather is happening in that direction at the time. And of course, north or northwest winds are able to tap into air from northern Canada which can be mild to cool in summer and cold to frigid in winter. The fact that the geographical center of North America is located within North Dakota's boundaries is more than just trivial information when it comes to North Dakota's weather. Proximity to an ocean makes weather more temperate. Summers are cooler and winters are milder if the wind is blowing in off an ocean due to the water's increased capacity for storing heat energy. But it is a very long way from North Dakota to the modifying effects of any ocean. And because weather generally comes from a westerly direction, air coming to North Dakota from the Pacific Ocean must travel up and over the Rocky Mountains to get here. And the western slopes of all those mountains catch essentially all of any modifying influences. So except for those times when low pressure systems are bringing surges of moisture northward the air over North Dakota tends to be rather dry. And dry air usually leads to rather large temperature swings from morning to afternoon. Chapter Eleven - Natural Resources 567
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