Southwest Climate Outlook August 2012

Date issued

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

Published by the Climate Assessment for the Southwest (CLIMAS), with support from University of Arizona Cooperative Extension, the Arizona State Climate Office, and the New Mexico State Climate office.

Disclaimer. This packet contains official and non-official forecasts, as well as other information. While we make every effort to verify this information, please understand that we do not warrant the accuracy of any of these materials. The user assumes the entire risk related to the use of this data. CLIMAS, UA Cooperative Extension, and the State Climate Office at Arizona State University (ASU) disclaim any and all warranties, whether expressed or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will CLIMAS, UA Cooperative Extension, and the State Climate Office at ASU or The University of Arizona be liable to you or to any third party for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of this data.