March 2012 Climate Summary
Drought: Drought conditions continue to expand and intensify across Arizona, while severe drought continues to grip much of New Mexico.
Temperature: Several storms in February resulted in slightly below-average temperatures in Arizona and western New Mexico. The storms dodged eastern New Mexico, causing warmer-than-average temperatures there.
Precipitation: Precipitation in most of Arizona and New Mexico has been less than 75 percent of average in the past month.
ENSO: The current La Niña event is running out of steam and is expected to end by late April. ENSO-neutral conditions are forecast to hold sway through the spring and summer seasons.
Climate Forecasts: Warming trends in recent decades are driving forecasts for above-average spring and summer temperatures in the Southwest. Precipitation forecasts for these periods, however, are less definitive—monsoon season forecasts have historically been about as accurate as a coin flip.
The Bottom Line: Below-average rain and snow is almost guaranteed for many parts of the Southwest this winter in large part because of La Niña's influence. Despite a recent winter storm that brought much needed moisture to the Southwest around March 18, snowpacks and precipitation across most of the region are mostly below average. Similar to last year, January and February were dry, and rain and snow tallied less than 50 percent of average in these months in many parts of the Southwest. As a result, drought has expanded and intensified, most notably in Arizona. The scant precipitation is also driving forecasts that call for a 40 percent chance that spring flows in the Verde, Salt, and Gila rivers will be less than 60 percent of average, while the Rio Grande likely will be less than 90 percent of average. The Upper Colorado River Basin, which received historically high snowpacks during last winter’s La Niña event, also likely will experience well below-average streamflows this spring and summer. While the La Niña event is expected to end in April, spring storms in the Southwest—most notably in Arizona—are often few and far between, presenting few opportunities to overcome shortfalls in precipitation before the monsoon begins.