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Published January 25, 2011
U.S. Drought Monitor(data through 1/18/11)
Data Source(s): U.S. Department of Agriculture, National Drought Mitigation Center, National Oceanic and Atmospheric Administration
An active winter storm pattern dominated much of the western U.S. over the past 30 days, bringing average to above-average precipitation to almost all areas except southern Arizona and most of New Mexico. This has kept much of the western U.S. drought free and has even beaten back some short-term drought conditions that were present in Nevada and northwestern Arizona in mid-December (Figure 3). Often called Pineapple Express storms, several unusually strong storms in middle to late December tapped moisture from the tropical Pacific Ocean and dropped copious amounts of precipitation across Southern California, southern Nevada, and northwestern Arizona. The 30-day precipitation totals are in excess of 400 percent of average in some of these regions. Overall, only 23 percent of the area in the western U.S. is experiencing abnormally dry conditions or worse. In the Southwest, moderate to severe conditions are being experienced in southern Arizona, New Mexico and eastern Colorado.
The U.S. Drought Monitor is released weekly (every Thursday) and represents data collected through the previous Tuesday. The inset (lower left) shows the western United States from the previous month’s map.
The U.S. Drought Monitor maps are based on expert assessment of variables including (but not limited to) the Palmer Drought Severity Index, soil moisture, streamflow, precipitation, and measures of vegetation stress, as well as reports of drought impacts. It is a joint effort of several agencies; the author of this monitor is Michael Brewer/Liz Love-Brotak, NOAA/NESDIS/NCDC.
The best way to monitor drought trends is to pay a weekly visit to the U.S. Drought Monitor website:
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