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Published March 24, 2011
Data Source(s): High Plains Regional Climate Center
The few storms during the 2011 water year (from October 1) generally have moved from southwest to northeast across the southwestern U.S. Virtually all of the winter storms have passed over the northwest corner of Arizona, while very few storms have moved through southern New Mexico or southeastern Arizona. This has left a precipitation gradient, with dry areas in the southeast receiving less than 50 percent of average precipitation and relatively wet areas to the northwest receiving 130 percent to more than 300 percent of average precipitation (Figures 2a–b). Most areas in between have received less than 70 percent of average. Southeastern San Juan County in northwestern New Mexico also received more than 300 percent of average precipitation. The pattern of the past 30 days has been very similar, with 150–300 percent of average precipitation along the lower Colorado River and the northwest corner of New Mexico, less than 5 percent of average across all of New Mexico except the northernmost counties, and 5– 50 percent of average precipitation in southeastern Arizona (Figures 2c–d). This is a typical pattern for a La Niña year, during which storms tend to remain well north of Arizona and New Mexico. The few storms that have come through the northwest corner of Arizona have tapped into subtropical moisture, resulting in very heavy rain or snow.Notes:
The water year begins on October 1 and ends on September 30 of the following year. As of October 1, 2010, we are in the 2011 water year. The water year is a more hydrologically sound measure of climate and hydrological activity than is the standard calendar year.
Average refers to the arithmetic mean of annual data from 1971–2000. Percent of average precipitation is calculated by taking the ratio of current to average precipitation and multiplying by 100.
The continuous color maps (Figures 2a, 2c) are derived by taking measurements at individual meteorological stations and mathematically interpolating (estimating) values between known data points. Interpolation procedures can cause aberrant values in data-sparse regions.
The dots in Figures 2b and 2d show data values for individual meteorological stations.
For these and other precipitation maps, visit:
For National Climatic Data Center monthly precipitation and drought reports for Arizona, New Mexico, and the Southwest region, visit:
Southwest Climate Outlook Staff
- Michael Crimmins, UA Extension Specialist
- Stephanie Doster, Institute of the Environment Editor
- Dan Ferguson, CLIMAS Program Director
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, CLIMAS Associate Staff Scientist
- Gigi Owen, CLIMAS Assistant Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Swetish, CLIMAS Publications Assistant
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
The CLIMAS Web site 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.... Read full disclaimer