1. 1 The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP June 27, 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, rainfall is much below normal over southwestern peninsular India, but above normal along the Gangetic plains of India, Nepal and over Burma.

4. 4 Precip Patterns: Last 30 Days The 30-day precipitation pattern is overall similar to the 90-day pattern. The distinct difference in the anomaly patterns in northeastern and south western parts of India is a sign of the general weakness in the monsoon circulation over India, and very possibly an indication of an ongoing “monsoon break” over India. Please see Note in Slide three.

5. 5 Precip Patterns: Last 7 Days Over the last seven days, except for the east-west band of precipitation over northeastern India and vicinity, the summer monsoon precipitation is below normal in general over much of the monsoon region. There is considerable discussion among monsoon meteorologists that the Indian monsoon region is under a “break monsoon” situation.

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 anomalous precipitation over the various regions India is relatively consistent with the spatial maps shown earlier.

7. 7 Atmospheric Circulation The anomalously high precipitation amount over northern India is quite consistent with a low level cyclonic circulation center near this region. The lack of precipitation over southern India is associated with the weak ridge west of coastal India in the northern Arabian sea.

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 July. Green (brown) shading indicates increase (decrease) in rainfall associated with strong monsoon. The NCEP Global Forecast System predicts that the Webster-Yang monsoon index (even though the precipitation associated with this index over the India region is not much) will lift up to near normal in the upcoming two weeks from much below normal level.

10. 10 Prediction of South Asian Monsoon Index 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 July. 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 (even though the precipitation associated with this index over the India region is not much) will be at near normal level in the next two weeks.

11. 11 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 fluctuating considerably as it has done in the past.

12. 12 Summary During the past 90 days, rainfall is much below normal over southwestern peninsular India, but above normal along the Gangetic plains of India, Nepal and over Burma. The 30-day precipitation pattern is overall similar to the 90- day pattern. The distinct difference in the anomaly patterns in northeastern and south western parts of India is a sign of the general weakness in the monsoon circulation over India, and very possibly an indication of an ongoing “monsoon break” over India. Over the last seven days, except for the east-west band of precipitation over northeastern India and vicinity, the summer monsoon precipitation is below normal in general over much of the monsoon region. There is considerable discussion among monsoon meteorologists that the Indian monsoon region is under a “break monsoon” situation. The anomalously high precipitation amount over northern India is quite consistent with a low level cyclonic circulation center near this region. The lack of precipitation over southern India is associated with the weak ridge west of coastal India in the northern Arabian sea. The NCEP GFS model continues to predict an overall weakened summer monsoon circulation for the next two weeks thus persisting the “break monsoon” like situation over India.

13. 13 Demise of the Asian Monsoon

14. 14 Onset of the Australian Monsoon

15. 15 Climatology