Precipitation

Precipitation since the water year began on October 1 has been well below normal on the Colorado Plateau, as well as in the southwestern quarter of both Arizona and New Mexico (Figures 2a–b). These areas, along with northeastern New Mexico, have received 50–90 percent of average precipitation. Central and southeastern Arizona and northwestern and east-central New Mexico have received 100–130 percent of average. A few isolated areas also have seen 130–200 percent of average precipitation, including northeastern Arizona, southeastern New Mexico, and the area near the Nevada-California-Arizona border. The spotty nature of the water year precipitation seems a bit unusual in an El Niño year, when winter precipitation tends to be more uniform. This year, however, the moisture source was inconsistent, and the winter storms tended to be localized.

A decrease in storm activity over the past 30 days left most of New Mexico with less than 50 percent of its average rainfall (Figure 2c). The southern half of Arizona has received 50–100 percent of average rainfall, with areas of southeastern Arizona receiving 110–300 percent of average. A large area covering northeast Arizona and northwest New Mexico has received 130–300 percent of average precipitation. For some areas the summer rainfall filled in gaps left by isolated winter storms, but in many cases the dry areas during the winter were also dry areas during the monsoon.