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Published November 21, 2012
Precipitation(data through 11/14/12)
Data Source(s): High Plains Regional Climate Center
Since the water year began on October 1, conditions across most of the Southwest have been exceptionally dry (Figures 2a–b). The one notable exception has been near the Arizona–California border and the far northeastern corner of New Mexico. However, small amounts of precipitation can cause above-average precipitation in these regions due to the historically low precipitation during the time. Outside of these areas, southern Arizona and western and central New Mexico have received less than 25 percent of their average precipitation for this time of year, and most areas have measured less than 50 percent of average. This is not uncommon for this period, especially if tropical storms emanating in the Pacific Ocean do not waft into the region.
The past 30 days also were very dry, particularly in the western third of Arizona and eastern New Mexico, both of which received less than 5 percent of average precipitation (Figures 2c–d). Only a small part of Gila County in central Arizona had near-average precipitation. In the last month, only one storm passed through the region, but it did not have much moisture to generate significant rainfall across the region. More low-pressure systems are expected to sweep across the West in the next several weeks. However, after a few months of expecting an El Niño event to develop and deliver wetter-than-average conditions to many parts of the Southwest, the forecast now is for ENSO-neutral conditions to persist through the winter. ENSO-neutral events, on average, deliver slightly below-average rain and snow to many parts of the Southwest. They also have brought both very wet and very dry conditions, which makes projecting winter precipitation difficult. La Niña events, on the other hand, almost always bring below-average precipitation to the region.Notes:
The water year begins on October 1 and ends on September 30 of the following year. As of October 1, 2012, we are in the 2013 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.
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