[Coral-List] CRW Reduces Outlook for Thermal Stress Potential in the Caribbean in 2009

Mark Eakin Mark.Eakin at noaa.gov
Tue Sep 15 17:11:23 EDT 2009

The NOAA Coral Reef Watch (CRW) Coral Bleaching Thermal Stress Outlook  
indicates that the potential for coral bleaching in the Caribbean in  
2009 has lessened. While there continues to be an elevated potential  
for higher than normal temperatures in 2009, severe thermal stress is  
less likely than earlier outlooks indicated. There is still some  
potential for thermal stress that may lead to bleaching along the  
Pacific coast of Mexico and islands in the equatorial central Pacific  
Ocean. So far, it appears unlikely that bleaching will be severe in  
those areas either.

  NOAA’s operational Climate Forecast System continues to call for El  
Niño development during 2009-10. If El Niño conditions continue to  
strengthen, this could increase the bleaching risk in the central to  
eastern Pacific and Caribbean late this year and next year. Remember  
that this guidance should be used as an indicator of potential general  
patterns rather than a precise predictor of thermal stress at any  

The full message with images can be found at: http://coralreefwatch.noaa.gov/satellite/bleachingoutlook/outlook_messages/bleachingoutlook_20090915_for_2009sepdec.html

Caribbean and Eastern Pacific Bleaching Outlook:

             Temperatures across the Caribbean have continued to be  
warmer than normal during 2009 and have continued to rise in many  
areas. However, in most parts of the basin we have not seen  
accumulation of thermal stress at levels that causes significant  
bleaching.  The current forecast model indicates that slightly  
elevated temperatures are likely to continue across the Caribbean  
basin through the end of the 2009 bleaching season. This is a marked  
improvement from concerns of prolonged high temperatures that were  
prompted by the models earlier in the year. Thermal stress may reach  
levels high enough to cause some bleaching, especially in the Lesser  
Antilles and the Caribbean coast of Central America. While significant  
accumulation of thermal stress is no longer expected, some areas still  
may be at some risk of bleaching.

  NOAA’s operational Climate Forecast System and other meteorological  
agencies continue to call for development of El Niño conditions during  
2009-10. Typically this has the strongest impact in the Caribbean  
during the second year of the El Niño (2010). With the developing El  
Niño, temperatures may continue to increase in the eastern Pacific  
Ocean off Mexico, posing a concern for some bleaching of coral reefs  
along that coast.

Pacific Bleaching Outlook:

             While there is still some indication that higher than  
normal temperatures may continue in the central equatorial Pacific  
from Kiribati to the Marshall Islands, the threat of significant  
accumulation of thermal stress has abated there as well. This region  
is also subject to intensification during El Niño conditions, so El  
Niño forecasts should be monitored in the coming months as any  
strengthening or weakening of the El Niño may change the potential for  

Current Bleaching Conditions:

Temperatures continue to be above normal and are rising in most of the  
Caribbean, but temperatures and thermal stress accumulation are not as  
high as those seen in August 2005, particularly around Puerto Rico and  
the Lesser Antilles. Only a few localized areas have experienced  
significant accumulation of thermal stress – of particular note are  
prolonged high temperatures in Florida Bay. Recently, the Caribbean  
Mexican and Belizean coasts of Central America, southern Cuba, Cayman  
Islands, and Jamaica have experienced the highest water temperatures  
of this decade and need to be closely monitored during the next month.  
Note: high thermal stress levels in the Gulf of Panama are the result  
of a known error in the climatology used for our products. CRW’s  
current HotSpot and DHW data should be disregarded in the Gulf of  
Panama until we release our new, Enhanced-50km version of the CRW  
products later this year.

  Temperatures across much of the Pacific are above normal, consistent  
with El Niño development. However, the Pacific coast of Mexico is the  
only reef-bearing area that has experienced significant accumulation  
of thermal stress.

About the Outlook System:

The Thermal Stress Outlook is based on sea surface temperature (SST)  
forecasts generated by the Linear Inverse Model (LIM) from the NOAA  
Earth System Research Laboratory.  In a normal year, the Outlook  
forecasts no potential for bleaching. When forecast SST exceeds  
bleaching thresholds over a long enough period to cause bleaching, 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. Two  
updates of the bleaching outlook system are currently being developed.  
The first will be a minor adjustment to the system now in use. The  
second will develop an entirely new outlook system that uses the  
operational Climate Forecast System (CFS) of the NOAA National Centers  
for Environmental Prediction in the way we now use the LIM model. We  
hope that the CFS-based version will be available for the 2010  
northern-hemisphere bleaching season and can be used to compare  
against the updated LIM-based system.

Our seasonal bleaching outlooks can be found at:


Current HotSpot and Degree Heating Week charts and data formatted for  
HDF and Google Earth can be found at: http://coralreefwatch.noaa.gov/satellite/index.html

Time series graphics for index sites can be found at: http://coralreefwatch.noaa.gov/satellite/current/sst_series_24reefs.html

and http://coralreefwatch.noaa.gov/satellite/current/experimental_products.html

You can sign up for automated bleaching alerts at: http://coralreefwatch-satops.noaa.gov/SBA.html

  Please report bleaching events (or non-events) at: http://www.reefbase.org/contribute/bleachingreport.aspx



C. Mark Eakin, Ph.D.
Coordinator, NOAA Coral Reef Watch
National Oceanic and Atmospheric Administration
Center for Satellite Applications and Research
Satellite Oceanography & Climate Division
e-mail: mark.eakin at noaa.gov
url: coralreefwatch.noaa.gov

E/RA31, SSMC1, Room 5308
1335 East West Hwy
Silver Spring, MD 20910-3226
301-713-2857 x109                   Fax: 301-713-3136
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"This is the generation that must also stop the spread of the  
pollution that is slowly killing our planet, from shrinking coastlines  
and devastating storms to widespread misery and famine and drought.  
The effects of climate change are now in plain sight."
Barack Obama, Apr. 3 2009

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