The University of Arizona

Southwest Climate Outlook January 2016 | CLIMAS


Southwest Climate Outlook January 2016

Thursday, January 21, 2016

In this Issue:

Precipitation: Over the past 30 days, the cumulative precipitation totals for Arizona and New Mexico were a mix of above- and below-average values (Fig. 1). Thirty-day averages often span wet and dry periods, while the week-to-week totals show considerably more variability. For example, precipitation totals in southern Arizona were buoyed by a series of storms that brought significant rainfall to the southwestern U.S. in the first week of January, which was preceded by a relatively below-average December and followed by an extended dry period in mid-January (see El Niño Tracker for more commentary and discussion of recent precipitation trends).

Temperature: December cooled off in much of the Southwest. Most of Arizona recorded normal to below-normal temperatures, while New Mexico was mostly normal to above normal, especially along the eastern half of the state (Fig. 2). Globally, 2015 was the warmest year on record and was among the top five warmest years for many western states (Fig. 3), and was the second warmest year on record for the U.S. overall.

Snowpack and Water Supply: Relatively frequent winter storm activity has brought impressive snowpack levels and snow water equivalent (SWE) percent of normal values to much of the western U.S., including above-normal values across almost all of the basins in Arizona and New Mexico (Fig. 4). Increased winter precipitation is an expected pattern given the current strong El Niño event. Later this spring, we will have a more accurate understanding of El Niño’s contribution to winter precipitation and a better sense of how temperature affected patterns of rain and snow and the contributions to water supply (See reservoir totals).

Drought: Long-term drought conditions persist across much of central and eastern Arizona along with the western edge of central New Mexico (Fig. 5). Recent runs of average to above-average precipitation have helped mitigate some of the short-term drought conditions, but we are continually reminded that multi-year droughts, such as those we experienced during much of the 21st century, will require multi-year periods to fully recover. El Niño offers hope for additional drought relief, particularly if above-average precipitation over the winter helps saturate soils and build snowpack in the region, boosting reservoir storage during springtime snowmelt runoff events.

El Niño Tracker: We are in the middle of a strong El Niño event forecast to remain in place through Spring 2016. We can expect variable weather throughout the winter season, but we anticipate more winter precipitation events and a higher cumulative total at the end of the cool season (see El Niño Tracker).

Precipitation & Temperature Forecast: The January 21 NOAA-Climate Prediction Center three month seasonal outlook predicts above-average precipitation for most of the Southwest this winter, with progressively increasing chances of above-average precipitation as you move south (Fig. 6, top). Temperature forecasts are split, with elevated chances for above-average temperatures along the West Coast and the Pacific Northwest, and increased chances for below-average temperatures centered over Texas and and southeastern New Mexico (Fig. 6, bottom).