This synoptic study for the period 13 to 16 July 1972, involved the use of surface, radiosonde, and radar observations, as welI as satellite pictures. Isentropic analyses indicated that the depth of the moisture with this surge of tropical air was of the order of 8,000 to 12,000 feet. A unique feature of this type of surge is its resemblance to a giant sea-breeze effect, where the main advective forces result from the low-level pressure gradient between the desert thermal low and the relatively higher pressures over the cooler Gulf of California. This effect is emphasized by the lack of upper-air support as shown in the mean vector winds from 10,000 to 20,000 feet for the period of concern. SateIIite photographs and film loops give a dramatic picture of the movement of the cloud mass associated with the surge. They also suggest that one of the mechanisms that may be a factor in the development of the cloudy, showery area at the mouth of the Gulf of California is an easterly wave. These extensive and active cloud areas apparently establish the low-level conditions favorable for the northward push of the surge

Three cases of extreme local precipitation within the Intermountain summer season were studied to determine the source of moisture for these events. The rains occurred at Phoenix, Ariz. on June 22, 1972 (133 mm in 2 hours), at Elko, Nev. on August 27, 1970 (105 mm in about 2 hours), and at Morgan, Utah on August 16, 1958 (about 150 rnm in 1 hour). Synoptic data were used to analyze surface and upper levelmoisture changes in time and space. In each case the study showed that a tongue of high moisture at low levels approached the vicinity of or encompassed the storm area prior to onset of the rain. The tongue of moisture was very narrow in reaching toward the Elko and Morgan storms and could be traced, through continuity of changes in pattern with time, back to the Gulf of California. The moisture is believed to be conveyed through the natural channel provided by the Gulf and the paralleling ridges. The low-level moisture followed a path controlled to some extent by major mountain barriers. A general conclusion is that greater emphasis should be given to tropical Pacific moisture in evaluating extreme summer precipitation values for the Intermountain region.

In this book, the authors integrate various perspectives on the evaluation of natural resources in arid and semiarid zones, analyze development options, and discuss systems analysis tools that could be important for the management of technology.

"During summer the interior of the United States and northern Mexico west of the Continental Divide experience frequent intrusions of moist tropical air. In the months of July and August the greatest northward flux occurs. June and September are transition months from spring to summer and summer to falI, respectively. During these months, particularly June, there is a predominance of rather dry air-mass conditions"--Introduction

This book presents a current review of the science of monsoon research and forecasting. The contents are based on the invited reviews presented at the World Meteorological Organization''s Fourth International Workshop on Monsoons in late 2008, with subsequent manuscripts revised from 2009 to early 2010. The book builds on the concept that the monsoons in various parts of the globe can be viewed as components of an integrated global monsoon system, while emphasizing that significant region-specific characteristics are present in individual monsoon regions. The topics covered include all major monsoon regions and time scales (mesoscale, synoptic, intraseasonal, interannual, decadal, and climate change). It is intended to provide an updated comprehensive review of the current status of knowledge, modeling capability, and future directions in the research of monsoon systems around the world.