Southwest Climate Outlook May 2009

Date issued

May Climate Summary
Drought–All watersheds in Arizona are experiencing drought, with abnormally dry conditions present across northern and western parts of the state and moderate drought conditions across southeast Arizona. Drought conditions expanded in New Mexico, where 78 percent of the state is experiencing some level of drought.
Temperature– Arizona and New Mexico have been 2 to 8 degrees warmer than average during the last month, with some record-breaking temperatures.
Precipitation– In the 30 days prior to May 20, most of Arizona had received less than 5 percent of average precipitation. However, in the two days following May 20, significant precipitation fell in the Southwest.
ENSO– Sea surface temperatures warmed to near-average conditions across the equatorial Pacific. Forecasts suggest neutral conditions are 70 percent likely to continue through July, with an increasing chance of El Niño conditions developing by late summer.
Climate Forecasts– Forecasters believe that the monsoon will arrive early and deliver above-normal precipitation in the first half of the season, but the rains may taper off in the second half of the summer. Temperature forecasts for most of the West show a tilt in the odds toward warmer-than-normal temperatures.

The Bottom Line– Temperatures were 6 to 8 degrees F above average across the high country areas of Arizona and New Mexico in early May, which led to rapid melting of the remaining snowpack. In May, Phoenix had 14 consecutive days in which temperatures equaled or surpassed 100 degrees, setting a new record. Also, recent heavy precipitation in the Southwest between May 20 and 23 added much needed rainfall to the driest time of year and helped reduce fire risk.

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.