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Published January 25, 2011
Data Source(s): High Plains Regional Climate Center
The Southwest has been generally dry since the water year began on October 1 but has experienced several periods of intense rain and snow. Storm tracks in November and December crossed Southern California and moved northeast across northwestern Arizona, leaving most of the Southwest with less than 75 percent of average precipitation (Figures 2a–b). The dry weather in many parts of both states is typical of the La Niña circulation that helped push storms north of Arizona and New Mexico. In the southern tier of both states, where La Niña typically causes drier conditions, precipitation has been less than 25 percent in New Mexico and less than 50 percent in Arizona. On the other hand, the northwestern corner of Arizona has received 150 to 800 percent of average precipitation, in large part from intense storms in middle and late December.
Virtually all the precipitation in the last 30 days fell in two storms at the end of December. All but the northwest quarter of New Mexico has had less than 50 percent of average precipitation in the past 30 days (Figures 2c–d). The northwest corners of both states have received 200 to 800 percent of average precipitation.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
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, Managing Editor, CLIMAS Associate Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Dollin, CLIMAS Publications Assistant
- Dave Dubois, New Mexico State Climatologist
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