Southwest Climate Outlook May 2013

Date issued

May Climate Summary

Drought: Severe drought has expanded across much of Arizona, while exceptional drought now covers about 44 percent of New Mexico.

Temperature: Warmer-than-average temperatures in Arizona and colder-than-average conditions in New Mexico dominated in the last month.

Precipitation: Although one storm wafted through the region in May, precipitation has been scant, which is typical for this time of year.

ENSO: ENSO-neutral conditions are expected to continue through the summer.

Climate Forecasts: The June–August forecast calls for increased chances for above-average temperatures in the Southwest, while precipitation may be below average in eastern New Mexico.

The Bottom Line: Drought conditions in New Mexico steadily worsened through the winter. Extreme and exceptional drought conditions cover about 82 percent of the state, an increase of approximately 70 percent since October 1. Drought conditions in Arizona are only slightly better, and both states experienced a third consecutive winter in which rain and snow was below average. Most of Colorado, from which much of the water in major southwestern rivers originates, also received below-average precipitation. Consequently, best estimates for spring streamflows in the Colorado River and Rio Grande, the Southwest’s most important rivers, are projected to be only 42 and 24 percent of average, respectively. With May and June historically dry months for Arizona and New Mexico, improvements in drought and water supply likely will not arrive until the monsoon begins in earnest. Fire activity will also ramp up in coming months, which is the typical pattern for this time of year—fires peak in June and July. The parched landscape, however, has fire managers expecting above-normal fire risk. At this point, relief from drought and drought-related impacts hinges on the timing and vigor of the monsoon. With dry and warm conditions in the Great Plains, there is some indication that the monsoon may arrive earlier than average. However, monsoon forecasts are highly uncertain and there is no guarantee that an early arrival translates to above-average rain. While a vigorous monsoon could dampen temperatures by increasing cloud cover and evaporative cooling, forecasts call for above-average temperatures, in part because of warming trends experienced in recent decades.

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.