Forecasts and Outlooks > Archive
Southwest Climate Outlook - April 2004

Date issued: April 22, 2004

A. Summary

Highlights

• Virtually all New Mexico reservoirs are still at well below-average levels.

•Storage in the major Colorado River reservoirs is still well below average. Forecasts for below-average inflow to Lake Powell are a major cause of concern for western water resource managers.

Temperatures - Temperatures have been above average during the past 30 days, continuing a long-term trend in the Southwest. Many temperature records were set in our region during March.

Precipitation - Early April precipitation brought much needed short-term drought relief to large areas of New Mexico and parts of southeastern Arizona. Water year precipitation for most of northern and western Arizona, however, is still below average. Early snowmelt and relatively low snowpack in the Southwest (including the Upper Colorado River Basin) will have ramifications for water supply and fire as we head toward summer.

Climate Forecasts - Seasonal forecasts indicate considerably increased probabilities of above-average temperatures across Arizona and most of New Mexico through the spring and summer months.

ENSO - ENSO conditions remain neutral. The best chance for an El Niño episode to develop is during the summer months. Chances for development of a La Niña episode are low.

The Bottom Line

Hydrological drought is expected to persist in most of the Southwest through the spring.

• The most likely scenario is that above-average temperatures will continue for the next several months, with implications for enhanced evaporation and curing of fuels for wildfire. The beginning of the fire season was delayed by recent precipitation; however, as we approach the warm, dry pre-monsoon season, fire potential is expected to increase rapidly, especially in Arizona.

•The worst case scenario that what remains of our winter snowpack is rapidly melted or evaporated by predicted above-average temperatures. Soil moisture is the first to “demand payment” during drought, and in a worst case scenario, years of soil moisture depletion result in further reduced reservoir inflows.

•The best case scenario that we receive some more precipitation during late spring. The NOAA-CPC May monthly outlook suggests slightly increases in the probability of above-average precipitation in eastern New Mexico. The probability of La Niña (dry, warm Southwest) is low.

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