Southwest Climate Outlook April 2011

Date issued

April Climate Summary

Drought– Unusually dry weather over the past 30 days has caused short-term drought conditions to continue to expand and increase in severity across much of New Mexico and Arizona, particularly southern regions of both states.

Temperature– Temperatures across the Southwest have been hotter than average in the past 30 days, with most of New Mexico and southeastern Arizona experiencing temperatures more than two degrees warmer than average.

Precipitation– Scant precipitation fell during the winter in most of the Southwest—New Mexico experienced its 6th driest winter of the last 116. That pattern has been upheld in the past 30 days—virtually no precipitation fell in most of New Mexico, while Arizona experienced patches of wetter- and drier-than-average conditions.

ENSO– The La Niña of 2010-11 is coming to an end, with sea-surface temperatures in the equatorial Pacific quickly warming to near-average levels for this time of year. ENSO-neutral conditions are expected to return by early summer.

Climate Forecasts– Forecasts call for a greater than 50 percent chance that temperatures will be above average through the spring and early summer. Equal chances of above-, below-, or near-average rainfall are projected through the summer.

The Bottom Line–La Niña was the headline of the winter, causing extremely dry conditions in Arizona and New Mexico. Precipitation in many southern parts of both states measured less than 25 percent of the historical average since October 1. January 2011 was the driest on record for New Mexico, and the October–March season was the sixth driest. Snowpacks were also low. However, not all the news is bad. A wet winter in the Upper Colorado Basin is fueling an above-average spring streamflow forecast for the Upper Colorado River, which will help boost storage in lakes Mead and Powell. With the upcoming months historically dry and warm in Arizona and New Mexico, the onus will be on the monsoon to deliver rain and stave the expanding and intensifying drought conditions: 12 and 33 percent of Arizona and New Mexico, respectively, are classified with extreme drought conditions. The dry winter combined with forecasts of continued parched conditions and warmer-than-average temperatures also are fanning an increased risk for wildland fires.

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.