Precipitation

While precipitation since the water year began on October 1 is much wetter than average across southern Nevada and the western border of Arizona, the wet pattern stops at the western counties of Arizona (Figures 2a–b).  The driest conditions have been in western New Mexico and southern Arizona where rainfall has been virtually absent. However, this is only an 18-day period and it is not unexpected to have dry conditions in October.  Elsewhere, northern Arizona is faring a little better than southern regions of the state, but precipitation is still well below average for October, as it is in east-central New Mexico.

An active monsoon in some regions, particularly southern and western Arizona, helped make up for precipitation deficits in these regions. However, the monsoon ended early in September and storms during the second half of the monsoon were more common in Arizona than New Mexico, leaving New Mexico very dry. Fortunately a few storms pushed across Texas into southeastern New Mexico in late September, and this area also benefitted from moisture from Hurricane Paul (Figures 2c–d). Also, in the last month, northeastern New Mexico benefitted from an early winter storm.

Looking ahead, precipitation forecasts do not provide any indication whether rain and snow will be above average or not in coming months. While an El Niño event is still likely on the horizon—which would increase chances for a wet winter—the state of ENSO has been looking more like ENSO-neutral in recent months. If neutral conditions persist, the region would still experience normal yearly variability in the number and intensity of winter storms.