Forecasts and Outlooks > Archive
Southwest Climate Outlook - September 2003

Date issued: September 26, 2003

A. Summary

Hydrological drought continues to be an enormous concern for the Southwest. Most New Mexico river basins remain in emergency drought status, and reservoir storage in virtually all New Mexico basins has declined during the past month. Current storage in the major Colorado River and interior Arizona reservoirs continues to decline.

Late summer rainfall brought short-term drought relief to some communities and ecosystems in north-central Arizona and along the Mogollon Rim. New Mexico, with the exception of north-central New Mexico, continues to be exceedingly dry. Based on historical records, both states will require on the order of 200% of average precipitation to end the drought during the next three months.

New Mexico and Arizona continue to exhibit poor range and pasture conditions (relative to state averages). Over 70% of New Mexico pasture and rangeland is in poor to very-poor condition. New Mexico topsoil is in the poorest condition of all of the lower 48 states.

Seasonal temperature forecasts indicate increased probabilities of above-average temperatures across Arizona and most of New Mexico through the winter months. Seasonal precipitation forecasts indicate very slightly increased probabilities of below-average precipitation across Arizona.

Due to neutral ENSO conditions, seasonal climate forecasts have a high degree of uncertainty.

Fire danger is near normal for our entire region.

Bottom line: Hydrological drought will continue in the Southwest during the next several months.

The most likely scenario is that autumn rainfall will not contribute significantly to reservoir recovery over most of the region. October and November precipitation rarely contributes significantly to annual totals (though October 2000 was a memorable exception in Arizona and New Mexico).

The worst case scenario takes two forms: (a) our region receives little autumn precipitation, resulting in increased long and short-term drought severity, (b) our region receives extremely high short-term precipitation, accompanied by flooding and severe erosion.

The best case scenario is that El Niño rebounds this fall and winter, providing increased chances of above-average precipitation. Neutral equatorial Pacific Ocean temperatures are expected to persist during the next several months, however, reducing forecast skill.

B. Recent Conditions >