A. Summary
	B. Recent Conditions
	C. Forecasts
	D. Forecast Verification

Diagnosing 2007 U.S. precipitation extremes (PDF, 200KB)

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Note: This work is published by the Climate Assessment for the Southwest (CLIMAS) project and the University of Arizona Cooperative Extension; and is funded by CLIMAS, Institute for the Study of Planet Earth, and the Technology and Research Initiative Fund of the University of Arizona Water Sustainability Program through the SAHRA NSF Science and Technology Center at the University of Arizona.

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, SAHRA, and WSP 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 Extention, SAHRA, WSP, 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

Joe Abraham, CLIMAS Assistant Staff Scientist
Deborah Bathke, New Mexico State Climatologist
Ashley Coles, CLIMAS Graduate Research Associate
Mike Crimmins, UA Extension Specialist
Stephanie Doster, ISPE Information Specialist
Gregg Garfin, ISPE Deputy Director of Outreach
Kristen Nelson, ISPE Associate Editor
Nancy J. Selover, Arizona State Climatologist

Forecasts and Outlooks:
Southwest Climate Outlook - April 2008

Date issued: April 23, 2008

A. Summary

Drought – Wet winter conditions helped keep short-term drought at bay across most of Arizona even with very dry conditions over the past thirty days. New Mexico has not faired as well with deepening drought conditions due to many months of below-average precipitation.

Temperature – Temperatures were above-average across much of Arizona and New Mexico over the past thirty days. Many locations across the Southwest observed temperatures at least 1–2 degrees F above-average.

Precipitation – Much of Arizona and New Mexico observed below-average precipitation again this past thirty days. Almost no measurable precipitation fell across Arizona and southern New Mexico during this period.

ENSO – The current La Niña event weakened considerably this past month with warming sea surface temperatures in the eastern and central Pacific as well as a weakening influence on atmospheric circulations. Most forecast models indicate a steady slide towards ENSO-neutral conditions by mid-summer 2008.

Climate Forecasts – Seasonal climate forecasts project above-average temperatures and an equal chances precipitation forecast as La Niña impacts on precipitation patterns across the Southwest wane into the spring.

The Bottom Line – The transition from wet and cool winter conditions to more typical warm and dry springtime conditions appears to be complete with storm tracks retreating north. La Niña continues to become less of a player in Southwest weather. Long-term temperature trends dominate the expectation of above-average temperatures through the summer.

Fire: Back in the news The Southwest Coordination Center reports that more than 150,000 acres already have burned in New Mexico in 2008, including several fires in excess of 5,000 acres each. In the Jemez Mountains of northern New Mexico, wildland firefighters have fought and controlled one blaze on national forest land near Gilman (Santa Fe New Mexican, April 4). Grasslands in southeastern New Mexico and southeastern Arizona, which have received scant precipitation since the start of the water year on October 1, are particularly at risk. Given recent dryness and high winds, several so-called red flag warnings have been issued for parts of Arizona and New Mexico, indicating that “critical fire weather conditions are either occurring or are imminent,” according to the National Weather Service. The Southwest Climate Outlook will continue to cover fire conditions and forecasts through the fall. For more info visit: http://gacc.nifc.gov/swcc/index.htm

This month's cover photo Theodore Roosevelt Lake, located near Phoenix in the Tonto National Forest, was formed by the construction of a masonry dam on the Salt River in 1911, making it the oldest artificial reservoir in Arizona. This photograph was taken on March 30th, on the southern edge of the lake near the Windy Hill Campground. Source: Steve Novy, ISPE