Temperature

Temperatures during the water year, which began Oct. 1, continue to depend on elevation. The coldest conditions have been at the highest elevations in both Arizona and New Mexico. The southwest deserts of Arizona, the lower Colorado River valley, and the southern border of New Mexico have been the warmest (Figure 1a). The winter storms that have tracked through the Southwest generally have passed over the northern portions of both states, and many storms have missed Arizona and New Mexico altogether. With few exceptions, Arizona was within 1 degree Fahrenheit of average statewide (Figure 1b). On the other hand, the highest departures from average temperatures have been in eastern New Mexico and only isolated locations have been colder-than-average (Figure 1b). Virtually no storms, dry or wet, crossed eastern New Mexico, which contributed to above-average temperatures in this region. The warmer-than-average water year thus far is the result of the La Niña circulation pattern that forced winter storms to pass north of Arizona and New Mexico.

In the past 30 days, the temperature pattern was controlled by the location of the subtropical high over the Southwest. The high pressure over eastern New Mexico pushed moisture and monsoon activity northward through eastern Arizona, leaving eastern New Mexico dry and therefore warmer than average. Northern Arizona was within 2 degrees F of average over the past month, the result of relatively constant thunderstorm activity. The southwest part of the state had a few days of activity in late July, but has been dry during most of August (Figures 1c–d).