Temperature

Temperatures during the 2012 water year were 1 to 3 degrees Fahrenheit warmer than average across large swaths of both Arizona and New Mexico, with temperatures in Arizona generally slightly cooler than in New Mexico (Figure 1a). The warmest regions were northeastern New Mexico and Gila County in Arizona, where temperatures were 2 to 4 degrees F warmer than average (Figure 1b). The La Niña event, which prevailed during the winter, kept most of the cold winter storms north of both states. Those storms that crossed the region tended to waft over northern Arizona, bypassing southern regions and New Mexico. This helped cause temperatures to be well above average in New Mexico. In Arizona, most areas also experienced above-average temperatures, although they were slightly cooler than New Mexico. The one exception, where temperatures were below average, was in south-central Arizona. In this area, several cold winter storm and strong summer thunderstorm activity delivered significant rainfall and lowered temperatures. In the Southwest, a strong positive correlation exists between the amount of precipitation and temperature.

The dry winter and spring weather gave way to an active monsoon season in Arizona. Summer storm activity was more frequent in the western part of the state, bringing copious rain to the lower Colorado River valley and across central Arizona and cooling air temperatures there. The general position of the tropical high pressure area, however, prevented moist air from rolling into New Mexico; consequently the state was dry and warmer than average during the monsoon.  

A view of the average temperatures for the water year reveals the impact topography has on temperature, with higher elevations cooler than lower areas (Figure 1a). Average temperatures on the Colorado Plateau, for example, were between 50 and 60 degrees F, with the highest mountains averaging between 40 and 50 degrees F.  Southeastern New Mexico recorded average temperatures of 55 to 65 degrees F, while the southwestern deserts of Arizona were warmest, at 65 to 75 degrees F.
 

Click figures to enlarge.

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