1. 1 The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP January 31, 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, as can be seen from the total, anomalous and percentile maps over land, precipitation has been generally near, above or much above normal over much of the monsoon region, except over southern, eastern China, the middle east and over parts of Papua New Guinea. 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 Even though the 90 day accumulated precip has been above normal over much of the season over large parts of the monsoon region, 30-day accumulation is beginning to show some deficiencies over eastern Australia and in the interior central regions. South eastern China continues the dryness developed earlier. Please see Note in Slide three.

5. 5 Precip Patterns: Last 5 Days Consistent with the NCEP GFS prediction last week, during the last seven days, monsoon rainfall was much below normal over much of northern and eastern Australia, which is probably a good thing, considering the flooding in these regions from the excessive precipitation earlier. Please see Note in Slide three. If land only maps are used, this map corresponds to the last seven days.

6. 66 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 The anomalous anti cyclonic circulation over interior eastern Australia is quite consistent with the below-normal rainfall in this region. Overall, the weakned monsoon circulation over the region this past week is quite consistent with the model forecasts..

8. 8 NCEP/GFS Model Forecasts Bias-Corrected Precip. Anom. for Weak 1 & Week 2 Week-1 Week-2 Note: The NCEP/GFS based Forecast maps are not updated this week due to technical difficulties. The maps shown here are from prev. week.

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 January. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the Webster-Yang monsoon index shows a light upward tick in the upcoming week and then return to normal the following week.

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 January. 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 shows a positive tick in the upcoming 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 December. 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) will return to near and above normal levels in the following two weeks.

12. 12 Summary During the past 90 days, precipitation has been generally near, above or much above normal over much of the monsoon region, except over the Middle East, southern and eastern China, and over parts of Papua New Guinea. However, 30-day accumulation is beginning to show some deficiencies over eastern Australia and in the interior central regions. In particular, consistent with the NCEP GFS model prediction last week, during the last seven days, monsoon rainfall was below normal over much of northern and eastern Australia, which is probably a good thing, considering the flooding in these regions from the excessive precipitation earlier. Models are predicting a slight uptick in the strength of the monsoon circulation in the upcoming two weeks.

13. 13 Demise of the Asian Monsoon

14. 14 Onset of the Australian Monsoon

15. 15 Climatology