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< Home Get Ready for Monsoon Madness!
Get out your most comfortable and casual tropical togs and plan to attend MONSOON MADNESS on Tuesday evening!
ASPRA members guarantee a great time as you enjoy a menu so scrumptious it would make Cookie at the chuck wagon blush! Your meal will be served at the world famous Rustlers Roost (www.rustlersrooste.com), high atop the Pointe at South Mountain Resort. Rustlers Roost not only offers some of the best Western fare this side of the Rio Grande, but you’ll also get to dance the night away and be rewarded with a spectacular view of Phoenix and the surrounding area. Each guest will get to chow down on ALL of the following:
We look forward to seeing you all. . . and when the Monsoon hits, get ready for the madness to begin! How can Arizona, a desert, have a monsoon like India? Actually one of the reasons that India has its more famous monsoon is largely due to the huge Rajasthan Desert in western India. But more fundamentally a 'Monsoon' is linked more to a wind shift rather than precipitation. In fact, the name "monsoon" is derived from the Arabic word "mausim" which means "season" or "wind-shift". Again, for India, during the winter dry period, the airflow comes from high pressure to the north—the dry Himalayas and Siberia. For the summer, the desert of western India heats up and low pressure forms. This causes air to swirl in from the west, the south and the east—all oceans! The result? HEAVY RAIN! The Arizona Monsoon is a well-defined meteorological event (technically called a meteorological 'singularity') that occurs during the summer throughout the southwest portion of North America. During the winter time, the primary wind flow in Arizona is from the west or northwest—from California and Nevada. As we move into the summer, the winds shift to a southerly or southeasterly direction. Moisture streams northward from the Pacific Ocean and the Gulf of Mexico. This shift produces a radical change in moisture conditions statewide. Such a change, together with daytime heating, is the key to the Arizona monsoon. This wind shift is the result of two meteorological changes:
These two features combine to create strong southerly flow over Arizona. The southerly winds push moisture north-ward from Mexico. The exact source region for the moisture of the Arizona monsoon is unknown. Researchers have proposed the Gulf of Mexico and/or the Gulf of California as the source regions but conclusive evidence has so far been elusive.This has lead to the creation of large data-collecting efforts and research programs such as SWAMP, the South-West Area Monsoon Project. By the way, the term "monsoons" as in "when the monsoons arrive ..." is a meteorological no-no. There is no such beast. The word should be used in the same manner that "summer" is used. Consequently, the proper terminology is "monsoon thunderstorms" not "monsoons." Monsoon thunderstorms are convective in nature. By that, we mean that the thunderstorms are powered by intense surface heating. In addition, strong moisture influx into Arizona is also required. The operational criterion for the onset of "monsoon" conditions used in Arizona is "prolonged (3 consecutive days or more) period of dew points averaging 55°F" or higher." There is nothing magical, however, about 55°F. It originally was linked to the total amount of water in the atmosphere above the weather station (a precipitable water amount of 1", a quantity thought to be necessary for convective thunderstorm activity). In general, for Phoenix, the temperature limits for the production of monsoon thunderstorms are 100° to 108°F with the optimum temperature being about 105°F. Temperatures needed to produce Tucson's thunderstorms are somewhat lower. The Arizona monsoonal circulation does not produce thunderstorms every day during the months of July-September but rather occurs in a pattern that has "Bursts" and "Breaks." According to climatologist Andrew Carleton: "Burst": a movement into Arizona of a weak trough in the upper level westerlies (normally during summer these winds are far north of this location) which spreads upper level cold air into the region. In lower levels, during a "burst", there is strong surface heating and strong southerly or southeasterly transport of moisture into Arizona. This creates intense atmospheric destabilization and leads to strong widespread thunderstorm outbreaks. "Break": an enhanced ridging of the upper level Bermuda and North Pacific subtropical high pressure systems which acts to stabilize the atmosphere and thereby cutoff widespread thunderstorm activity. Our own meteorologists suggest that a break usually occurs when the subtropical ridge re-develops over NW Mexico and drier air spreads into Arizona.
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