Temperature

Temperatures since the water year began on October 1 have generally followed the terrain, with the warmest conditions in the southwest deserts of Arizona, and the coldest conditions on the Colorado Plateau of northern Arizona and New Mexico (Figure 1a).  The temperature pattern reflects the trajectory of cold winter storms that have passed through Nevada and Utah and dipped down into northern Arizona before wafting northeast through New Mexico. The southeastern half of New Mexico missed out on most of the cold fronts, but an occasional storm that tracked through northern Mexico kept southern New Mexico’s temperatures cooler than the otherwise would have been. In general, temperatures are within 2 degrees F of average across most of both states, with most areas being warmer than average (Figure 1b). Only a few isolated spots had significantly colder-than-average temperatures.

In the past 30 days, high pressure has dominated the atmospheric circulation pattern, bringing warm, dry air up from Mexico and setting new records for both daytime highs and high nighttime low temperatures. As a result, all of Arizona and New Mexico experienced unseasonably warm conditions (Figures 1c–d). There was also a large west-east temperature gradient, with temperatures in Arizona warmer than in New Mexico. This gradient was caused by high pressure systems that were more persistently parked over Arizona. The excessive heat early in the season, combined with a very dry spring, dried out grasses and is contributing to high wildfire danger (see page Wildland Fire Outlook).