Mid-West Summer Weather and the Way of Least Friction

A typical summer weather event in the mid-west starts with a cool dry wind moving south near the Rocky Mountains and an equal mass of warm moist air moving north to the east of it in a side by side arrangement. Arguments supporting this proposition include observations, theory and one assumption. Observations are an awareness of the predominately north/south wind directions at one point in northwest Iowa for more than 30 consecutive summers as well as knowledge of the eastward flourishing vegetation distribution throughout the mid-west starting at the Rockies. The theory is the expectation that in geophysical flows the configuration most likely to persist and be observed has the least amount of friction among all possibilities. One assumption is that only a single southward cold wind takes place at one time to initiate the weather “cycle”.