Southwest Climate Outlook April 2013

Date issued

April Climate Summary

Drought: Severe and extreme drought covers 43 and 94 percent of Arizona and New Mexico, respectively—an increase in the extent of drought in both states in the past month.

Temperature: Temperatures have been 1–5 degrees Fahrenheit above average in most of Arizona and New Mexico, with even warmer temperatures in southwest New Mexico.

Precipitation: Most of Arizona and New Mexico have experienced precipitation deficits ranging from 0.25 to 1.0 inches in the last 30 days, and much of both states has experienced less than 70 percent of average precipitation.

ENSO: ENSO-neutral conditions still hold sway in the Pacific Ocean and are expected to remain through the summer.

Climate Forecasts: Warming trends and other indicators suggest warmer-than-average conditions are in store for the May–July period in the Southwest; forecasts also call for below-average precipitation in northern Arizona and in all of New Mexico, but with higher uncertainty.

The Bottom Line: Precipitation since January 1 in Arizona and New Mexico has been a case of the good, the bad, and the ugly. The Mogollon Rim region of Arizona has benefitted from near- to above-average rain and snow and drought conditions there have improved, making it the only region in all of Arizona and New Mexico without at least abnormally dry conditions. Precipitation outside the Mogollon Rim region, however, has been largely less than 70 percent of average. New Mexico has fared the worst. Precipitation has measured less than 50 percent of average in most areas, and extreme drought conditions have expanded from 12 percent on November 6 to about 59 percent on April 18. For both states, the November–March period marks the third consecutive winter in which total precipitation was below average. Conditions this winter prompted fire managers to expect elevated chances of significant fire risks in May. The Upper Colorado River Basin and upper Rio Grande also experienced dry conditions this winter, resulting in below-average streamflow projections. For example, streamflows for the Colorado River are likely to be around 34 percent of average for the April–July period. If this projection comes to pass, it will mark the fourth lowest flow since Lake Powell became operational. The third lowest was recorded last year. Streamflow forecasts for the Rio Grande call for less than 33 percent of average. Dry conditions will be the norm until the monsoon begins, usually in late June or early July. Without the presence of a strong El Niño or La Niña—neutral conditions currently hold sway—forecasting the monsoon’s onset likely will be no better than flipping a coin. However, temperature forecasts for the early summer call for increased chances for warmer-than-average conditions, based in part on trends 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.