Home » February 2013 Southwest Climate Outlook
Published February 27, 2013

February Climate Summary

Drought: While slight improvements in short-term drought conditions occurred in parts of central Arizona, drought intensified in central New Mexico.

Temperature: Temperatures between January 22 and February 20 were within two degrees of average, except in eastern New Mexico, which was warmer than average.

Precipitation: Five winter storms blew through Arizona in the last 30 days, bringing above-average precipitation to many parts of the state. These storms, however, missed most of New Mexico.

ENSO: The current ENSO-neutral event is expected to remain through the spring.

Climate Forecasts: March–May forecasts call for above-average temperatures and below-average precipitation in all of Arizona and New Mexico.

The Bottom Line: Five storms in the last month helped cut winter precipitation deficits, particularly in the higher elevations of Arizona. However, when viewed with a longer-term lens, dry conditions still remain the norm. This is particularly true for New Mexico, because recent storms have missed most of the state. Since January 1, for example, precipitation has been less than 70 percent of average in many parts of New Mexico and drier in central regions. Arizona has received slightly higher totals. Even with recent rain and snow, drought conditions remain widespread and intense in both states. Nearly 83 percent of Arizona and 98 percent of New Mexico are classified with moderate or more severe drought. Temperatures since January 1 have been between 3 and 6 degrees F below average in most of the higher elevations of Arizona, New Mexico, Colorado, and Utah. This has helped keep snowpacks larger than they otherwise would be. Nonetheless, water contained in snowpacks, or SWE, is generally below average in the Southwest. Many monitoring stations in the Upper Colorado River Basin and Rio Grande headwaters report less than 80 percent of average SWE, fueling below-average spring streamflow forecasts for the region’s two largest rivers. It is looking increasingly unlikely that reservoirs on these and other rivers in the Southwest will get a boost from above-average precipitation, particularly since forecasts are calling for increased chances for below-average rain in coming months. Thin snowpacks coupled with potentially warm temperatures and dry conditions have resource managers concerned for an elevated risk of wildfires in the spring.

Research Highlight: A 470-year record of the Southwest monsoon

A recent study used tree rings to reconstruct 470 years of the monsoon for a region covering much of southeast Arizona and southwest New Mexico, where the monsoon is most vigorous in the U.S. The study, led by UA graduate student Daniel Griffin and CLIMAS investigator Connie Woodhouse, among other researchers, revealed that droughts in the last five centuries have been characterized not just by below-average winter precipitation, but also by failed summer rains. The monsoon fizzled during the 17th century drought, for example, leading to famine and, consequently, an uprising by Pueblo Indians against Spanish colonizers, according to some scholars. With the exception of the past decade, the absence of successive dry seasons helped stave off protracted droughts that have been more prevalent in past centuries. This suggests, the authors state, that the last century may not be ideal for characterizing monsoon precipitation.

While tree rings have provided accurate estimates of past climates, most of them have reflected winter precipitation. The study’s results now provide the longest tree-ring record of monsoon season precipitation, which can help resource managers better plan for drought.

The article is published in the journal Geophysical Research Letters. Read the abstract and/or access the entire article (subscription required) at: http://onlinelibrary.wiley.com/doi/10.1002/grl.50184/abstract