Southwest Climate Outlook November 2012

Date issued

November Climate Summary

Drought: The drought picture remains largely unchanged from one month ago. Moderate to extreme drought covers all of Arizona and New Mexico.

Temperature: Warmer-than-average temperatures continue to be the norm in the Southwest, upholding recent trends toward a warmer fall and early winter.

Precipitation: Dry conditions have prevailed in the last month, which is not uncommon for this time of year.

ENSO: The prospect of an El Niño event faded this past month. ENSO-neutral conditions are now expected to persist through the winter season.

Climate Forecasts: Precipitation outlooks call for increased chances for drier-than-average conditions in January through March, while temperature outlooks suggest warmer-than-average conditions this winter.

The Bottom Line: Drought conditions across the Southwest are widespread, with only about 1 percent of Arizona and New Mexico not experiencing at least moderate drought. These conditions reflect both short-term drought, which accumulates over several months, as well as the persistence of longer-term rain and snow deficits. In the last six years, for example, most of the Southwest has received between 71 and 90 percent of average precipitation. The past two years were especially dry, as back-to-back La Niña events helped divert winter storms north of the region. Water supply is one measure of long-term drought impacts, and currently low storage in the region’s reservoirs paints a grim picture. Combined, the 15 reservoirs in New Mexico are only about 19 percent full. In Arizona, reservoirs on the Verde and Salt rivers have decreased 36 percent in the last two years and contain only about half of their 2.3 million acre-feet storage capacity. Lakes Mead and Powell are also storing about half of their capacity. The next several months will go a long way toward determining if water supply and drought conditions improve or deteriorate. While the winter outlook called for above-average precipitation only a few months ago, that forecast has dissipated, along with a once-promising El Niño. Now, ENSO-neutral conditions are expected and historically have had lower odds of bringing above-average precipitation to the Southwest. In fact, an ENSO-neutral event coupled with other current factors contributes to an outlook for increased chances for below-average precipitation and above-average temperatures for most of the winter. If conditions are warmer, more rain may fall instead of snow, especially at mid-elevations, and spring snowmelt may begin earlier in the year, as has been the case in recent years.

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.