1. 1 The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP November 22, 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 much of southern Asia, tropical eastern Indian Ocean, tropical far western North Pacific, and Australia. Above-average rainfall was also seen over Northeast China and North Korea. On the other hand, below-average rainfall was observed over southern India, southern Indo-China peninsula, Malaysia, southern Japan, equatorial western Pacific, and Madagascar.

4. 4 Precip Patterns: Last 30 Days During the past 30 days, above-average rainfall occurred over much of 15S-20N, 80E- 140E. The southern Tropics including the eastern Indian Ocean, northern Australia and part of Indonesia experienced highly above average rainfall. On the other hand, below- average rainfall was observed much of the regions west of 80E and east of 140E except east of Australia. Below-average rainfall was also found over the southern hills of Tibetan Plateau, southern-eastern China, and Korea.

5. 5 Precip Patterns: Last 5 Days The Asian-Australian monsoon rainfall was mainly near average. Above-average rainfall was observed over the central South China Sea and tropical eastern Southern Indian Ocean. Below-average rainfall was found over much of the tropical Indian Ocean and western Pacific Ocean.

6. 6 Atmospheric Circulation An anomalous cyclonic pattern was observed over the Arabian Sea and India. Anomalous anti-cyclonic patterns were seen over the tropical western Pacific and off northwestern Australia. In addition, anomalous westerly flow and easterly flow were found over the tropical Indian Ocean and Pacific Ocean, respectively.

7. 7 NCEP/GFS Model Forecasts Bias-Corrected Precip. Anom. for Weak 1 & Week 2 Week-1 Week-2

8. 8 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 Webster-Yang monsoon index will continue to be above normal in the next two weeks.

9. 9 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 monsoon circulation over Southeast Asia and northwestern Pacific will be mainly near normal.

10. 10 Prediction of Australian Monsoon Upper panel: Australian monsoon index (Hung and Yanai 2004) defined as U850 averaged over 2.5ºS-15ºS, 110-150ºE. Positive (negative) values indicate strong (weak) than normal monsoon. Lower panel: Correlation between rainfall and Australian monsoon index (Hung and Yanai 2004; 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 Australian monsoon index will be fluctuating around normal.

11. 11 Summary The Asian-Australian monsoon rainfall was mainly near average. Above-average rainfall was observed over the central South China Sea and tropical eastern Southern Indian Ocean. Below-average rainfall was found over much of the tropical Indian Ocean and western Pacific Ocean. The NCEP Global Forecast System predicts that the monsoon circulation will be stronger than normal or near normal over southern Asia, and be fluctuating around normal over northern Australia in the next two weeks.

12. 12 Demise of the Asian Monsoon

13. 13 Onset of the Australian Monsoon

14. 14 Climatology