NOAA Coral Reef Watch Experimental Global Seasonal Coral Bleaching Thermal Stress Outlook Product (CFS-based)

The NOAA Coral Reef Watch (CRW) experimental global Seasonal Coral Bleaching Thermal Stress Outlook product at 1x1 degree spatial resolution described here is based on sea surface temperature (SST) forecasts generated by an operational, dynamical, fully coupled ocean-land-atmosphere seasonal climate forecast model, the NOAA/National Weather Service/National Centers for Environmental Prediction's (NCEP) Climate Forecast System (CFS) Version 2. The CFS-based Outlook significantly enhances CRW's capability for predicting the likelihood of coral bleaching up to four months (typical length of a bleaching season) into the future. With four CFS forecast runs per day, with lead-time up to 9 months into the future, CRW is able to produce a probabilistic Seasonal Outlook with 28 ensemble members at the weekly time scale. Currently on the Outlook product's webpage, CRW displays the CFS-based Seasonal Outlook at probabilities of 90% and 60%, thereby identifying the lowest thermal stress levels that 90% and 60% of the 28 ensemble members predict, respectively. Also displayed are four images of the percentages of the 28 ensemble members reaching each of the four coral bleaching thermal stress levels (Bleaching Watch & Higher, Bleaching Warning & Higher, Alert Level 1 & Higher, and Alert Level 2). The corresponding weekly outlooks that the Seasonal Coral Bleaching Thermal Stress Outlook is derived from are also provided to show development of potential thermal stress conditions on the weekly basis. This Seasonal Outlook is updated weekly, currently every Tuesday (U.S. Eastern Time). The first version of CRW's CFS-based Seasonal Coral Bleaching Thermal Stress Outlook prodcut, based on SST forecasts from CFS Version 1, was released to the public in July 2012. In December 2012, the second version of the CFS-based Outlook was released, by upgrading the system to use SST forecasts from the operational CFS Version 2 (CFSv2), which replaced CFSv1. In a normal year, the Outlook forecasts no potential for bleaching. When the forecasted SST exceeds bleaching thresholds over a long enough period to cause bleaching, however, the Outlook maps display the bleaching potential. Actual conditions may vary due to model uncertainty, subsequent changes in climatic conditions, extreme localized variability, or weather patterns. This effort is made possible through collaboration between NCEP and CRW, supported by funding from NCEP and the NOAA Coral Reef Conservation Program.