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Note: This work is published by the Climate Assessment for the Southwest (CLIMAS) project, The University of Arizona Cooperative Extension, and the State Climate Office at Arizona State University; and is funded by CLIMAS, and the Institute of the Environment.
This packet 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. The user assumes the entire risk related to the use of this data. CLIMAS, UA Cooperative Extension, and the State Climate Office at Arizona State University disclaim any and all warranties, whether expressed or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will CLIMAS, UA Cooperative , and the State Climate Office at Arizona State University or The University of Arizona be liable to you or to any third party for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of this data. Read full disclaimer
Mike Crimmins, UA Extension Specialist
Stephanie Doster, Institute of the Environment Associate Editor
Dan Ferguson, CLIMAS Program Manager
Gregg Garfin, Institute of the Environment Deputy Director for Outreach
Zack Guido, CLIMAS Associate Staff Scientist
Rebecca Macaulay, Graphic Artist
Nancy J. Selover, Arizona State Climatologist
Forecasts and Outlooks > Archive
Southwest Climate Outlook - July 2009
Date issued: July 21, 2009
A. Summary
The July 21, 2009 outlook is also available in a single, downloadable, printer-friendly file. [July 2009 PDF, 3.07 MB]
Requires Adobe Acrobat Reader. |
Drought– Monsoon rains have helped ease drought conditions in Arizona, particularly in the southeast region. The rains also have helped New Mexico, decreasing the extent of moderate and severe drought conditions.
Temperature– Only a few areas in western New Mexico and southern Arizona have had below-average temperatures.
Precipitation– Predictions of an early and wet monsoon have come true for central and southeast New Mexico and south-central Arizona.
ENSO– The NOAA-Climate Prediction Center has officially declared an El Niño event. El Niño conditions are expected to continue to develop during the next several months, evolving into a weak to moderate event that lasts through the 2009–10 winter.
Monsoon– The forecast for the 2009 monsoon called for an early start to the rainy season accompanied by above-average precipitation for the first half of the season. After the first month of rains, the forecast appears to have been accurate.
Climate Forecasts– Late summer and fall forecasts for much of the Southwest indicate temperatures similar to the warmest 10 years of the 1971–2000 observed conditions. Forecasters are uncertain about summer to fall precipitation because El Niño events can either increase or decrease rainfall.
The Bottom Line– The monsoon season so far has lived up to expectations, arriving early and with above-average rains in some parts of both states. However, because the past few monsoon seasons have been very wet, this season may seem dry. August storms are expected to deliver more rain to the parched Four Corners region, and rains elsewhere will continue to improve short-term drought conditions.
| Wet or Dry in the Second half of the Monsoon Season?
El Niño’s impact on the Southwest will be felt, it’s just not yet clear how. The forecasts issued by the NOAA-Climate Prediction Center (NOAA-CPC) calls for equal chances that August–October precipitation will be above-average, below-average, or average for all of Arizona and the southwestern half of New Mexico (see Figure 11a). Forecasters are uncertain because of a rapidly forming El Niño event in the tropical Pacific Ocean, which often is associated with two phenomena that have opposite effects on precipitation in the Southwest. On one hand, El Niño events can stifle summer rains in Arizona and New Mexico because they weaken and/or reposition the subtropical high that guides moisture into the Southwest. On the other hand, El Niño events also can foment a higher number of tropical storms, some of which deliver copious rains to the Southwest. While the first month of the monsoon season followed predictions, exhibiting an earlier-than-average onset and above-average precipitation for many parts of Arizona and New Mexico, forecasters are more hesitant to predict what’s next. “We’ll have to wait and see,” said Erik Pytlak, science and operations officer for the National Weather Service in Tucson. “It’s going to be interesting.” | This month's cover photo
Sheets of rain soak Hopi villages on Second Mesa in Northeast Arizona in May. |
Source: Dan Ferguson, CLIMAS. May, 2009,
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