Southwest Climate Outlook August 2009

Date issued

August Climate Summary
Drought– The extent of drought has increased in Arizona but decreased in eastern New Mexico, where drought severity also has decreased.
Temperature– Seasonal temperatures have been above average in most of the Southwest, with some record-breaking temperatures in Arizona during July.
Precipitation– Despite an early and wet monsoon burst across the southern portion of the Southwest, seasonal and water year precipitation totals are below average, except in southeastern New Mexico.
ENSO– A weak El Niño event is in progress and is expected to strengthen as fall approaches. El Niño usually increases the chances of above-average winter half-year precipitation in the region.
Climate Forecasts– Forecasts for the fall indicate temperatures similar to the warmest 10 years of the 1971–2000 observed conditions. Forecasts for the winter season indicate slightly increased chances of above-average precipitation in the southern half of the region.
The Bottom Line– After a timely onset, the monsoon has fizzled in most of the Southwest. Summer precipitation deficits have decreased rangeland and vegetation health across much of the region, with the major exception of southeastern New Mexico. Forecasts hold the promise of somewhat increased chances of winter season precipitation as an El Niño episode continues to develop in the tropical Pacific Ocean

Published by the Climate Assessment for the Southwest (CLIMAS), with support from University of Arizona Cooperative Extension, the Arizona State Climate Office, and the New Mexico State Climate office.

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