The APEC CLIMATE CENTER Climate Outlook for March August 2017 BUSAN, 24 February 2017 Synthesis of the latest model forecasts for March to August 2017 (MAMJJA) at the APEC Climate Center (APCC), located in Busan, Korea, indicates positive temperature anomaly across the off-equatorial Pacific and Atlantic with the positive El Niño-Southern Oscillation (ENSO) phase. The forecast for MAM 2017 shows positive temperature anomalies are likely to prevail over the off-equatorial Pacific and Atlantic. Dry conditions are highly probable in the equatorial Pacific. The forecasts for JJA 2017 suggest a persistent positive temperature anomaly over the off-equatorial Pacific and Atlantic. Below normal rainfalls are probable over Caribbean Sea and the central Indian Ocean to the maritime continent. Current Climate Conditions In December through early February, the ENSO phase was neutral. The strongest positive seasonal mean temperature anomalies exceeding +5 o C were observed over the Arctic. The negative temperature anomalies below -1 o C spanned Siberia to the northern Africa. Positive precipitation anomalies prevailed over the maritime continent, Australia, and the northern and southern Africa. Negative precipitation anomalies spanned the central Pacific and the central Indian Ocean.
Fig. 1. Seasonal mean anomalies of the observed surface air temperature (1 December 2016 10 February 2017). Fig. 2. Seasonal mean anomalies of the observed outgoing longwave radiation (1 December 2016 10 February 2017).
Forecast Sea Surface Temperature and ENSO Outlook: Positive Sea Surface Temperature (SST) anomalies in the central and eastern equatorial Pacific are expected to persist and be enhanced through August 2017, which means the El Niño is expected to develop. Slightly warm conditions are expected in the Indian Ocean without any significant zonal gradient, which is consistent with a neutral state of the Indian Ocean Dipole (IOD). Fig. 3. Predicted Niño 3.4 Index from individual models (A, B, C, D, E, and F) and the simple composite Multi-Model Ensemble (MME) method (SCM). Fig. 4. Predicted Indian Ocean Dipole mode index (IODMI) from individual models (A, B, C, D, E, and F) and the SCM.
Fig. 5. Spatial distributions of forecasted SST anomalies for March August 2017 over the tropical Indo-Pacific. Top panel shows SST anomaly forecast for March May 2017 and bottom panel shows SST anomaly forecast for June August 2017.
Temperature and Precipitation Outlook: 1. Forecast for March May 2017 Strongly enhanced probability for above normal temperature is predicted for the tropical and subtropical Atlantic, the northern North Atlantic and the Barents Sea, the southern Indian Ocean, and the off-equatorial belts of the Pacific. Enhanced probability for above normal temperature is predicted for the maritime continent and the northern Indian Ocean. Enhanced probability for below normal temperature is predicted for some parts of austral seas. Enhanced probability for above normal precipitation is predicted for the northeastern part of maritime continent, the eastern equatorial Pacific, and southern Africa. Strongly enhanced probability for below normal precipitation is predicted for the central Indian Ocean. Enhanced probability for below normal precipitation is predicted for the southern part of maritime continent, Australia to New Zealand, and the eastern subtropical Pacific. Precipitation in the central and eastern equatorial Pacific is predicted to be near normal. 2. Forecast for June August 2017 Strongly enhanced probability for above normal temperature is predicted for the tropical and subtropical Pacific, the off-equatorial Atlantic, and the southern Indian Ocean to Tasman Sea. Enhanced probability for above normal temperature is predicted for the Arctic, the eastern and southern Eurasia, and the eastern and western Indian Ocean. Enhanced probability for below normal precipitation is predicted for the Caribbean Sea, Great Australian Bight, and the central Indian Ocean. Precipitation in the equatorial Pacific is predicted to be near normal. The APEC Climate Center is a major APEC science facility, which was established in November 2005 during the leaders meeting of the Asia-Pacific Economic Forum in Busan, Korea. It produces seasonal and monthly forecasts of climate conditions for all seasons around the globe. APCC collects seasonal forecasts from 16 institutes in the APEC region: the Australian Bureau of Meteorology, Meteorological Service of Canada, Beijing Climate Center China, Institute of Atmospheric Physics China, Japan Meteorological Agency Japan, Korea Meteorological Administration Korea, Pusan National University Korea, Met Office United Kindom, Euro-Mediterranean Center on Climate Change Italy, Hydrometeorological Research Center of Russia, Voeikov Main Geophysical Observatory of Russia, Central Weather Bureau Chinese Taipei, National Aeronautics and Space Administration USA, National Centers for Environmental Prediction USA, International Research Institute for Climate and Society USA, Center for Ocean-Land-Atmosphere Studies USA. The APCC climate forecasts are based on model simulations from 16 prominent climate forecasting centers and institutes in the APEC region. These forecasts are collected and combined using state-of-the-art schemes to produce a statistically consensual forecast. The APCC forecasts are based not just on the magnitude of the seasonal changes that are predicted, but also take into account their simulated probability. Further details as well as the verification for the forecasts on a long term basis are available at http://www.apcc21.org. Historical verification of the forecast performance is based on a retrospective forecast period of all the models for the period 1983-2005.
Fig. 6. Deterministic MME seasonal 2m temperature forecast for March May 2017. Fig. 7. Probabilistic MME seasonal 2m temperature forecast for March May 2017.
Fig. 8. Deterministic MME seasonal precipitation forecast for March May 2017. Fig. 9. Probabilistic MME seasonal precipitation forecast for March May 2017.
Fig. 10. Deterministic MME seasonal 2m temperature forecast for June August 2017. Fig. 11. Probabilistic MME seasonal 2m temperature forecast for June August 2017.
Fig. 12. Deterministic MME seasonal precipitation forecast for June August 2017. Fig. 13. Probabilistic MME seasonal precipitation forecast for June August 2017.