For the past week, the subtropical jet stream has been drawing Pacific moisture into the American southwest; with cold air in place, this has produced the first significant snowfalls in the mountains of Arizona and New Mexico in the past few years. Now, the jet has angled more to the east, sending a plume of moisture across Mexico and into Texas. Heavy rains are forecast for western and central Texas, a welcome though temporary relief from a multi-year drought.
It is humbling to realize how much our lives are affected by the fickle motion of air currents. Our rudimentary understanding of the forces that guide them leave us guessing at the severity of our winters and, as 2006 demonstrated, make the art of hurricane forecasting seem like pure folly.
