Southwest Climate Outlook - El Niño Tracker - March 2020
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.
Positive sea surface temperature (SST) anomalies remain in the equatorial Pacific, particularly in the western regions (Figs. 1-2). Despite lingering warm waters, forecasts expect overall conditions will stay in the range of ENSO-neutral through at least summer 2020.
Forecast Roundup: On Mar 3, the Australian Bureau of Meteorology maintained their ENSO outlook at an inactive status, seeing “little or no sign of El Niño or La Niña developing in the coming months.” On Mar 12, the NOAA Climate Prediction Center (CPC) issued its ENSO diagnostic discussion with an inactive alert status. The CPC called for a 65-percent chance of ENSO-neutral through spring 2020 and a 55-percent chance of ENSO-neutral lasting through summer. They highlighted that while SSTs were near the El Nino threshold in the short term, forecaster consensus was for a gradual decline of these positive anomalies, and with oceanic and atmospheric conditions to remain consistent overall with ENSO-neutral through at least mid-2020. On Mar 12, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), noting a “split between neutral and weak El Nino conditions” in the short-term, but that they expect conditions to remain ENSO-neutral overall. On Mar 10, the Japanese Meteorological Agency (JMA) maintained its call for a 60-percent chance of ENSO-neutral conditions to last until summer 2020. The Feb 2020 North American Multi-Model Ensemble (NMME) continues steady movement into ENSO-neutral territory and is forecast to remain there at least through early summer (Fig. 4).
Summary: Much like last month, positive SST anomalies persist, and some of the forecasts even reference El Nino conditions. Also similar to the previous month, none of the forecasts see much chance of an El Nino event…why? The positive SSTs reflect warmer than average oceanic conditions and are occasionally in the range of weak El Nino thresholds. To be considered an El Nino event, the three-month average would need to stay above this threshold for five consecutive months. The atmosphere would also need to cooperate (often called ‘oceanic-atmospheric coupling’). Current forecasts do not expect these positive SST anomalies to last long enough to meet the El Nino criteria, much less see sufficient evidence in atmospheric conditions. ENSO-neutral remains by far the most likely outcome. As we noted last month, in the Southwest, ENSO-neutral winters have produced some of the wettest and driest winters (and everything in between). We continue to monitor sub-seasonal and short term forecasts for insight into upcoming events.
- Figures 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