1. 1 The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP April 11, 2011 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, precipitation has been generally near normal over much of the monsoon region, except for below normal rainfall over eastern China and over parts of Papua New Guinea. Over central and northern Australia, the seasonal mean precipitation associated with the northeast monsoon has been above normal. Note: Occasionally when the update date of the land+ocean precip maps are not close enough to the release date of this weekly scheduled monsoon ppt. we use the more recent land -only precip maps.

4. 4 Precip Patterns: Last 30 Days The 30-day precipitation accumulation is seriously deficient over southeastern China. Some pockets of dryness have also developed over north western portions of South Asia, particularly over Afghanistan and northern Pakistan, even though these regions so not receive much rainfall during this season. Elsewhere the precipitation is much above normal, particularly all along northern Australia. Please see Note in Slide three.

5. 5 Precip Patterns: Last 7 Days During the last seven days, rainfall continues to be deficient over southeastern China, sporadic elsewhere with some heavy downpour in certain spots across south Asia and northwestern Australia. Please see Note in Slide three. If land only maps are used, this map corresponds to the last seven days.

6. 6 Rainfall Time Series over 5x5 lat-lon boxes Note: This unified land-only daily precipitation dataset is different from the CMAP dataset used in the previous three spatial maps. The time series of precipitation over the various regions is quite consistent with the spatial maps shown earlier, even though as noted above, the precip data sets are from different sources and are processed differently.

7. 7 Atmospheric Circulation Continued slight ridging over southeast China is associated with below normal rainfall in that region. A small and weak cyclonic circulation over northwestern Australia brought more rainfall in this region.

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 March. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the Webster-Yang monsoon index continues to trend downward over the past few weeks. This index is more appropriate for northern summer monsoon than the during the current months now.

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 March 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 Southeast Asian and northwestern Pacific monsoon index will be at or slightly above normal level in the next two weeks.

11. 11 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 March Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the Australian monsoon circulation (over northern Australia) indicates at or slightly about normal levels of rainfall.

12. 12 Summary During the past 90 days, precipitation has been generally near normal over much of the monsoon region, except for below normal rainfall over eastern China and over parts of Papua New Guinea. Over central and northern Australia, the seasonal mean precipitation associated with the northeast monsoon has been above normal. The 30-day precipitation accumulation is seriously deficient over southeastern China. Some pockets of dryness have also developed over north western portions of South Asia, particularly over Afghanistan and northern Pakistan, even though these regions so not receive much rainfall during this season. Elsewhere the precipitation is much above normal, particularly all along northern Australia. During the last seven days, rainfall continues to be deficient over southeastern China, sporadic elsewhere with some heavy downpour in certain spots across south Asia and northwestern Australia. The NCEP GFS model predicts weak rainfall activity over the south Asia region in the next two weeks.

13. 13 Demise of the Asian Monsoon

14. 14 Onset of the Australian Monsoon

15. 15 Climatology