1. 1 The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP 2 November 2009 For more information, visit: http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/Asian_Monsoons/Asian_Monsoons.shtml http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/Asian_Monsoons/Asian_Monsoons.shtml

2. 2 Outline Recent Evolution and Current Conditions Monsoon Prediction Summary Climatology

3. 3 Rainfall Patterns: Last 90 Days During the past 90 days, below-average monsoon rainfall was observed over India, eastern Indo-China peninsula, southern China, East Asia, and the East China Sea. Below-average rainfall was also observed over Indonesia, Malaysia, tropical-subtropical southern Indian Ocean, and eastern Australia. Rainfall was above average over Bangladesh, Myanmar, northern Bay of Bengal, the South China Sea, northern Philippines, the Philippine Sea, the western Pacific, and equatorial Indian Ocean.

4. 4 Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was clearly below average over the tropical central- eastern Indian Ocean, southern India, and Sri Lanka. Below-average rainfall was also found over eastern Indo-China peninsula, East Asia, Indonesia, Malaysia, and southern Philippines. Rainfall was above average over the northern Bay of Bengal, Bangladesh, northern South China Sea, northern Philippines, and part of the western Pacific.

5. 5 Rainfall Patterns: Last 5 Days Rainfall was overall below average over South Asia, Southeast Asia, and their adjacent tropical oceans. Above-average rainfall was observed over the waters south of Japan, tropical western Indian Ocean, and equatorial western Pacific.

6. 6 Rainfall Time Series over 5x5 lat-lon boxes *This unified land-only daily precipitation dataset is different from the CMAP dataset used in the previous three spatial maps. From Southeast Asia to northern Australia, rainfall has been mostly below average over many locations, consistent with the El Nino conditions in the tropical Pacific Ocean.

7. 7 Atmospheric Circulation Anomalous cyclone affected northern Philippines and Taiwan, and anomalous easterlies appeared over the tropical Indian Ocean. The trade wind over tropical western Pacific was clearly weaker than normal.

8. 8 NCEP/GFS Model Forecasts Bias-Corrected Precip. Anom. for Weak 1 & Week 2 Week-1 Week-2

9. 9 Prediction of Large-Scale Monsoon Circulation Upper panel: Webster-Yang monsoon index (Webster and Yang 1992) defined as U850 (0- 20ºN, 40-110ºE) – U200 (0-20ºN, 40-110ºE). Positive (negative) values indicate strong (weak) than normal monsoon. Lower panel: Correlation between rainfall and Webster-Yang monsoon index (Webster and Yang 1992; shading) and regression of 850-mb winds on the monsoon index (vectors) for November. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the large-scale monsoon circulation over tropical Asia will weaker than normal in the next two weeks.

10. 10 Prediction of East Asia – NW Pacific Monsoon Upper panel: East Asia – Western North Pacific (EAWNP) monsoon index (Wang et al. 2008) defined as U850 (5-15ºN, 40-80ºE) – U850 (20-30ºN, 70-90ºE). Positive (negative) values indicate strong (weak) than normal monsoon. Lower panel: Correlation between rainfall and East Asia – Western North Pacific monsoon index (Wang et al. 2008; shading) and regression of 850-mb winds on the monsoon index (vectors) for November. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that, in the next two weeks, the EAWNP monsoon circulation will be overall near normal.

11. 11 Summary Rainfall was overall below average over South Asia, Southeast Asia, and their adjacent tropical oceans. Above- average rainfall was observed over the waters south of Japan, tropical western Indian Ocean, and equatorial western Pacific. The NCEP Global Forecast System predicts that in the next two weeks the large-scale Asian monsoon circulation will be weaker than normal, with overall below-average precipitation over East-Southeast Asia.

12. 12 Retreat of the Asian Monsoon

13. 13 Climatology