Home » August 2012 Southwest Climate Outlook
Published August 22, 2012

August Climate Summary

 

Drought: While monsoon precipitation has brought some short-term relief to parts of the Southwest, long-term drought conditions continue to plague all of Arizona and New Mexico.

Temperature: Temperatures have been near average in most of Arizona, while eastern New Mexico has continued to bake.

Precipitation: The monsoon has continued to track across the western border of Arizona, delivering substantial rains but leaving much of New Mexico extremely dry.

ENSO: Neutral conditions continue across the eastern Pacific Ocean, but a weak to moderate El Niño is expected to develop in the next few months.  

Climate Forecasts: A materializing El Niño event is expected to bring wetter-than-average conditions to southern Arizona and New Mexico this fall and winter. Cool temperatures, also associated with an El Niño, will likely counter recent warming trends, and forecasts are unclear which will win out.

The Bottom Line: Precipitation deficits that have accumulated over the past two years continue to paint the region with long-term drought. About 94 percent of Arizona and 85 percent of New Mexico are classified with severe drought or a more extreme drought category. One reason for these classifications is that many of the region’s important reservoirs are low. The most probable inflow volume into Lake Powell for the 2012 water year is projected to be 5.15 million acre-feet, or 48 percent of average. If this comes to pass, Colorado River streamflows will go down as the third lowest on record. A similar scene is playing out in New Mexico. Irrigation allotments from Elephant Butte Reservoir, which provides water to New Mexico’s most productive agricultural region, were only 10 inches; 36 inches is considered a full allotment. While an active second half of the monsoon will help ease short-term drought conditions, it will not erase them or cause substantial rebounds in reservoir storage. A protracted stretch of average to above-average precipitation will be necessary to bring conditions back to normal. The good news is that an impending El Niño event could bring much-needed moisture. Experts expect El Niño conditions to develop during the August–October period and persist through the winter. Although El Niño events historically deliver above-average precipitation to the region, the odds of copious rain and snow are not a sure bet. The Southwest has experienced dry conditions during past El Niño events

News Flash: Warming in Arizona from urbanization alone could approach 4 degrees C

Population growth and its attendant urban expansion play an important role in local temperature change. This is particularly true in the Southwest, home to the most rapidly expanding megapolitan region in the country—Arizona’s Sun Corridor. A recent peer-reviewed article showed that future warming is caused by local urban development, which can be substantial, and greenhouse gas-induced global climate change. It also showed that building practices can mitigate some magnifying effects of built environments.

In the Nature Climate Change study published in August, the authors used a climate model to analyze the impacts of high and low urban growth scenarios developed by the Maricopa Association of Governments. Based on the high growth scenario, results showed that urban expansion could increase average June–August temperatures by as much as 4 degrees Celsius (about 7 Fahrenheit) by 2050. The magnitude of this warming outpaces that of some projections of global warming caused by increased levels of greenhouse gases. The research also included a high growth scenario in which all roofs reflected 88 percent of solar rays, which would meet Environmental Protection Agency Energy Star rating requirements. The research found that reflective coating could reduce development-related warming substantially.

Read more at: https://geoplan.asu.edu/georgescu-megapolitan