Southwest Climate Outlook - El Niño Tracker - February 2019
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.
After months of El Niño on the horizon (but each month not appearingto get any closer), forecasters have identi ed the convergence ofatmospheric and oceanic conditions that indicate the presence of a weak El Niño event. This is expected to last through spring, although there is not complete agreement across the international agencies. On Feb. 12, the Japanese Meteorological Agency (JMA) maintained their assertion of the presence of El Niño conditions inthe equatorial Pacific and called for a 70-percent chance of these conditions lasting until summer 2019. On Feb. 14, the NOAA Climate Prediction Center (CPC) switched to an El Niño advisory, given the convergence of oceanic and atmospheric conditions, as well as warm subsurface waters on the way, but their outlook dropped to a 55-percent chance of an El Niño lasting through spring. On Feb.19, the Australian Bureau of Meteorology remained in an El Nino watch, reflecting the increased chance of an El Niño developing over spring and summer. On Feb. 19, the International Research Institute (IRI) issued an ENSO Quick Look, highlighting above-average sea surface temperatures (SSTs), warm subsurface waters, and the development of atmospheric conditions over the past few months. They maintained a 65-percent chance of an El Niño Feb-Apr, and a 50-percent chance Apr-Jun (Fig. 3). The North American Multi-Model Ensemble (NMME) points toward a weak El Niño at present lasting through spring 2018 (Fig. 4).
Summary: Sea surface temperatures (SSTs) are still above-average across the equatorial Pacific (Figs. 1-2), and atmospheric conditions finally caught up – the question is: will it be too late for the Southwest, or have we already been observing borderline weak El Niño impacts? The delayed convergence of oceanic and atmospheric conditions was the main factor holding back a more confident outlook, but 2018-2019 looks like it will be classified as a weak El Niño event. In the Southwest, El Niño is associated with increased chances for above-normal winter precipitation, but weak events demonstrate limited correlation with increased precipitation, and some of the wettest winters in the Southwest have been under ENSO-neutral conditions. Winter thus far in parts of Arizona and New Mexico line up with the narrative of winters under El Niño, but direct attribution is challenging given small sample size, aforementioned weak correlations, and the challenges in tracking precipitation anomalies in a region that already sees relatively infrequent rain events in a “wet” year. Additionally, it remains to be seen whether this will turn out to simply be a normal southwestern winter, which only feels wetter and cooler after multiple warm and dry winters altered expectations.
- Figure 1 - Australian Bureau of Meteorology - bom.gov.au/climate/enso
- Figure 2 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov
- Figure 3 - International Research Institute for Climate and Society - iri.columbia.edu
- Figure 4 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov
- Equatorial Niño Regions - For more information: ncdc.noaa.gov/teleconnections/enso/indicators/sst/
- Madden Julian Oscilation - For more information: cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjo.shtml