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Published April 27, 2011
Data Source(s): High Plains Regional Climate Center
Storm tracks during the winter progressed from southern California northeastward across the northwestern corner of Arizona. Some of the larger storms crossed into central Arizona and a few moved across northern Arizona and northern New Mexico, dropping copious precipitation on higher-elevation locations. The precipitation pattern displayed a strong northwest-to-southwest gradient, ranging from 200–300 percent of average in northwestern Arizona to 50–70 percent of average across central and northeastern Arizona and northern New Mexico, to less than 50 percent of average in southeastern Arizona and eastern New Mexico, and less than 25 percent of average across southern New Mexico (Figure 2a).
The last 30 days brought virtually no precipitation to the southeastern three-fourths of New Mexico, while parts of northwestern New Mexico and southwestern Arizona received above-average rain and snow (Figures 2c–d). The wettest areas, with 100-130 percent of average, are the Sangre de Cristo Mountains in north-central New Mexico and McKinley County, New Mexico. Arizona’s wet spots include central Apache, northern Coconino, central Pinal, central and western Pima, and eastern Yuma counties. Most of Cochise County received less than 25 percent of average precipitation during the month. However, even the wettest areas are relatively dry, as rainfall totals across the Southwest have been less than half an inch in the past month.
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