1. 1 The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP October 11, 2010 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 Precip Patterns: Last 90 Days During the past 90 days, above-average rainfall was observed over 10S-30N/60E-140E including much of southern Asia, tropical Indian Ocean, and far western North Pacific. Above-average rainfall was also seen over the Koreas. On the other hand, below-average rainfall was observed over southern India, southern Indo-China peninsula, Malaysia, southern Japan, equatorial western Pacific Ocean, and Madagascar.

4. 4 Precip Patterns: Last 30 Days During the past 30 days, above-average rainfall occurred over much of the tropical Indian Ocean and the waters near tropical Asia. Above-average also occurred over the southern hill the Tibetan Plateau, the Hainan Island (China), and Indonesia. On the other hand, below-average rainfall was observed over southern India, southern Indo-China peninsula, Malaysia, northern-central China, the Philippines, part of western Pacific, and Madagascar.

5. 5 Precip Patterns: Last 5 Days During the past several days, rainfall over the tropical Asian lands was mainly below or near average. Below-average rainfall was also observed over the western Pacific. On the other hand, above-average rainfall occurred over the Hainan Island (China), the Bay of Bengal especially the northern part, central Indonesia, and central-eastern Indian Ocean.

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. Upper panel: The accumulated rainfall over southern China has been clearly above average due to the heavy post monsoon rainfall. Middle panel: Rainfall over the northern Philippines has been mostly below average in the past 30 days. Lower panel : In the past season, the accumulated rainfall over much of Indonesia has been continuously above average.

7. 7 Atmospheric Circulation In the past week, cyclonic patterns were observed over the Hainan Island (China) and northern Bay of Bengal. Anomalous westerlies and easterlies appeared over the tropics of Indian Ocean and western Pacific, respectively.

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 October. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the Webster-Yang monsoon index will be above normal in the next two weeks.

10. 10 Prediction of South Asian Monsoon Circulation Upper panel: South Asian monsoon index (Goswami et al. 1999) defined as v850 (10- 30ºN, 70-110ºE) – v200 (10-30ºN, 70-110ºE). Positive (negative) values indicate strong (weak) than normal monsoon. Lower panel: Correlation between rainfall and South Asian monsoon index (Goswami et al. 1999; shading) and regression of 850-mb winds on the monsoon index (vectors) for October. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the South Asian monsoon circulation will be near normal in the next two weeks.

11. 11 Prediction of East Asian Monsoon Upper panel: East Asian monsoon index (Li and Zeng 2002; GRL). Positive (negative) values indicate strong (weak) than normal monsoon. Lower panel: Correlation between rainfall and East Asian monsoon index (Li and Zeng 2002; shading) and regression of 850-mb winds on the monsoon index (vectors) for October 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 East Asian monsoon circulation will be near normal.

12. 12 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 October 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 monsoon circulation over Southeast Asia and northwestern Pacific will be stronger than normal.

13. 13 Summary During the past several days, rainfall over the tropical Asian lands was mainly below or near average. Below-average rainfall was also observed over the western Pacific. On the other hand, above-average rainfall occurred over the Hainan Island (China), the Bay of Bengal especially the northern part, central Indonesia, and central-eastern Indian Ocean. The NCEP Global Forecast System predicts that the monsoon circulation over southern Asia will be mainly near normal or stronger than normal in the next two weeks.

14. 14 Demise of the Asian Monsoon

15. 15 Climatology