The characteristics of a number of recurrent weather systems observed in the Rocky Mountains and western United States will be examined under the direction of Professor Bosart. While case studies of some weather systems first appeared in literature several decades ago, little has followed since. One example is the so called "Nevada low", which generally forms in spring east of the Sierras when the 500 mb flow is southwesterly. A precursor lee trough is often seen from Oregon to southern Nevada. What are the life cycle, dynamic and thermal structures of the Nevada lows? Do they play any role in the later cyclogenesis downstream? If so, how? These Nevada lows are believed to be different from Colorado or Mediterranean lows, mostly attributed to differences in the physical dimensions and characteristics of local terrain. Besides leading to a better understanding, a careful study should also aid in the interpretation and utilization of predictions from numerical models.
