Southwest Climate Outlook December 2018 - Climate Summary
Assistant Research Professor, Arizona Institutes for Resilience
Assistant Professor of Anthropology, School of Anthropology
Ben McMahan joined CLIMAS after completing a PhD in Sociocultural Anthropology at the University of Arizona. His dissertation research was on hurricanes and disaster on the U.S. Gulf Coast, where he focused on
- Human interactions in dynamic social and environmental contexts,
- Risk perception and landscape changes during and after disaster, and
- Social network and policy responses to governance issues related to the acute threats of disaster; as they layer onto long term environmental issues and landscape scale changes.
He was also a key contributor to UA Bureau of Applied Research in Anthropology (BARA) collaborative/trans-disciplinary research on the social, economic, and environmental impacts of the US Oil and Gas industry (2007-2011), and the aftermath of the Deepwater Horizon oil spill (2010-2013).
At CLIMAS, his research activities included tracing how climate information is incorporated into regional decision maker networks, leading CLIMAS team research on the risks and effects of climate extremes, and collaborative research on the effects of climate variability on phenology and temporality of native plants in the region. He was also responsible for working to develop collaborative research opportunities and outreach efforts at CLIMAS, and as part of ongoing assessment and science/strategic planning, he contributed to strategic planning used to prioritize future research and outreach directions. He also coordinated publication of the monthly Southwest Climate Outlook, produced the Southwest Climate Podcasts, and was the online editor for CLIMAS’ blog - Southwestern Oscillations.
November Precipitation and Temperature: After a wetter- and cooler than-average October, November was closer to long-term averages. Precipitation ranged from average to below-average in Arizona and New Mexico (Fig. 1a). Temperatures were mostly within the range of average, with some below-average observations in eastern New Mexico and the Four Corners region, and with a region of above-average temperatures on the Arizona/California border (Fig. 1b).
Seasonal & Annual Precipitation and Temperature: Autumn (Sept-Nov) precipitation was average to much-above average, save for a small pocket of below-average rainfall in northwestern New Mexico (Fig. 2a), while temperatures for the same period were average to above average throughout Arizona and New Mexico (Fig. 2b). Year-to-date precipitation ranges from record driest to much-above average, with the marked precipitation deficit continuing in the Four Corners region (Fig. 3a). Year-to-date temperature maps reduce the effect of monthly variability and reveal much-above-average temperatures across most of the Southwest, including some local areas of record-warmest conditions (Fig. 3b).
Drought: The Dec. 11 U.S. Drought Monitor (USDM) highlights the presence of drought across the entire Southwest, with persistent and severe drought conditions in the Four Corners region (Fig. 4). Drought in the Southwest poses a challenge in mapping different timescales and intensities of drought on a weekly basis. In a region already characterized by dry conditions, where accumulated precipitation deficits build over seasons and years, these drought characterizations can struggle to capture all of these inputs. The 36-month standardized precipitation index (SPI) for the Southwest (Fig. 5) highlights differential patterns of drought and precipitation deficit.
Snowpack & Water Supply: Snow water equivalent (SWE) has fluctuated considerably in southern Arizona and New Mexico this fall, with current values generally near or below average as of Dec. 15 (Fig. 6). Reservoir storage remains a persistent concern, as water levels have been impacted by long-term drought and accumulated precipitation deficit. Most of the reservoirs are at or below their long-term averages, and a few of the Rio Grande reservoirs are especially low (see Arizona and New Mexico reservoir storage).
El Niño Tracker: An El Niño event appears imminent, with oceanic indicators now well into El Niño territory while atmospheric indicators continue to lag behind. Most forecasts noted a lack of coupling between ocean and atmosphere but remain confident of an El Niño event during winter 2018-2019, with forecast probabilities hovering around an 80- to 90-percent likelihood (see El Niño Tracker).
Precipitation and Temperature Forecast: The three-month outlook for December through February calls for increased chances of above-normal precipitation in most of Arizona, New Mexico, and northern Mexico (Fig. 7, top), and mostly equal chances of above- or below-average temperatures for the southwestern United States and northern Mexico (Fig. 7, bottom).
- Figures 1-3 - National Centers for Environmental Information - ncei.noaa.gov
- Figure 4 - U.S. Drought Monitor - droughtmonitor.unl.edu
- Figures 5-6 - Western Regional Climate Center - wrcc.dri.edu
- Figure 7 - International Research Institute for Climate and Society - iri.columbia.edu