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Published August 21, 2013
Monsoon Summary(data between June 15-August 15, 2013 )
Data Source(s): Western Regional Climate Center
The first half of the monsoon produced generally wetter-than-average conditions across much of the Southwest, particularly in southeast Arizona (Figure 9a). However, the monsoon has been spotty, and the spatial extent of rainfall in July was different than in August.
The monsoon started off around July 1 in southeast Arizona and slightly later in regions to the north. For many locations in both Arizona and New Mexico, the monsoon delivered more than 200 percent of average precipitation in July. Storms in the White Mountains and San Francisco Peaks areas, as well as the Rio Grande Valley in central New Mexico, doused the landscape with more than two inches of rainfall. Rain gauges at airports in major metropolitan areas in Arizona and New Mexico—Yuma, Phoenix, Tucson, and Albuquerque—logged above-average rain (El Paso has also received above-average rain). The hardest hit region was around Douglas along the Mexico-U.S. border in Arizona. The Douglas airport recorded 10.12 inches of rain, making it the wettest July there since 1948. A series of low-pressure systems boosted wet conditions. One of these originated in the Gulf of Alaska and flowed over Canada and the northern United States before dipping south toward Pennsylvania where it began wafting West. Eventually, this system meandered into the Southwest, where it lingered for several days. Systems like this tend to bring overnight showers and thunderstorms with activity lasting into the early morning, modifying the usual pattern of afternoon rainfall.
The first two weeks of August were generally dry for most of southern Arizona and in the metropolitan areas noted above, whose airports have yet to record substantial rainfall. Douglas and many regions in New Mexico, however, continue to experience copious rain. Combining July and August precipitation, even with dry conditions in some parts, paints the Southwest as generally wetter than average (Figures 9b–c). This is welcome news for a region in the throes of widespread drought, which has improved slightly since the monsoon began (see Arizona and New Mexico Drought Status).Notes:
The continuous color maps (figures at right) are derived by taking measurements at individual meteorological stations and mathematically interpolating (estimating) values between known data points. Interpolation procedures can cause aberrant values in data-sparse regions.
Average refers to the arithmetic mean of annual data from 1971–2000. Percent of average precipitation is calculated by taking the ratio of current to average precipitation and multiplying by 100. Departure from average precipitation is calculated by subtracting the average from the current precipitation.
Data obtained from the High Plains Regional Climate Center:
Southwest Climate Outlook Staff
- Michael Crimmins, UA Extension Specialist
- Stephanie Doster, Institute of the Environment Editor
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, Managing Editor, CLIMAS Associate Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Dollin, CLIMAS Publications Assistant
- Dave Dubois, New Mexico State Climatologist
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
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