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The Asian-Australian Monsoon System: Recent Evolution,

Current Status and Prediction

Update prepared byClimate Prediction Center / NCEP

September 17, 2012

For more information, visit:

http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/Asian_Monsoons/Asian_Monsoons.shtml

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Outline• Recent Rainfall and Current Conditions

• Monsoon Prediction

• Summary

• Climatology

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Precip Patterns: Last 90 Days

During the past 90 days, southern India, Thailand, Malaysia, Cambodia, Laos, Sumatra/Jakarta islands of Indonesia, and southwestern Australia had below normal rainfall. Central and eastern India had above normal rainfall. Severe shortages that existed over India at the end of July had almost vanished by the recent above normal rains.

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Precip Patterns: Last 30 Days

The 30-day precipitation anomaly pattern over much of northern India was much above normal to bring the earlier deficits considerably down. According to the India Met. Dept. (IMD) the all India Monsoon Rainfall (AIMR) from 1st June thru the 17th of September is now deficient by only about 6 % from their long term normal. This deficiency was as high as 20% just a few weeks ago.

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Precip Patterns: Last 7 Days

This past week, Gujarat, northwest and northwest regions including parts of Pakistan received above normal rainfall.

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Rainfall Time Series over 5x5 lat-lon boxes

The time series of precipitation over the various regions is pretty much consistent with the spatial maps shown earlier.

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Atmospheric Circulation

The anomalous cyclonic circulation in the low level flow was associated with copious rainfall over northeast India..

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

Week-1

Week-2

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SummaryDuring the past 90 days, southern India, Thailand, Malaysia, Cambodia, Laos, Sumatra/Jakarta islands of Indonesia, and southwestern Australia had below normal rainfall. Central and eastern India had above normal rainfall. Severe shortages that existed over India at the end of July had almost vanished by the recent above normal rains. The 30-day precipitation anomaly pattern over much of northern India was much above normal to bring the earlier deficits considerably down. According to the India Met. Dept. (IMD) the all India Monsoon Rainfall (AIMR) from 1st June thru the 17th of September is now deficient by only about 6 % from their long term normal. This deficiency was as high as 20% just a few weeks ago.

This past week, Gujarat, northwest and northwest regions including parts of Pakistan received above normal rainfall. NCEP/GFS’s forecasts indicate opposite patterns of rainfall amounts over India in week1 and week 2 periods with below normal rainfall amounts over central and peninsular India in the first week and large rainfall deficits over northeastern India in the second week. It is not clear at this time if the monsoon season over India ending in September (as measured by IMR index) will end as a normal season or slightly below.

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Demise of the Asian MonsoonDemise of the Asian Monsoon

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Onset of the Australian MonsoonOnset of the Australian Monsoon

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ClimatologyClimatology