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Saturday, May 19, 2012

Weekly Hydro-meteorological Report, 17 May 2012



Weekly Monitoring: During the week of 08th May-14th May rainfall ranged between 0-50 mm. On the 8th & 9th rainfall was observed for the Southeastern & Eastern regions & Mulativu &, Vavuniya districts. On the 13th no rainfall was observed for the entire country. 

Monthly Monitoring: During April, the entire island has shown an above average rainfall. 

7 Day Prediction: During next week, an accumulated rainfall of 5 mm -55 mm is predicted for the Southern half of the island. 
IMD WRF Model Forecast & IRI forecast: WRF Model Predicts less than 3 mm rainfall for the coastal regions of Puttalam, Gampaha & Colombo districts on 18th May 2012. On 19th less than 36 mm is predicted for the Colombo & Kalutara districts and spread till Kegalle, Ratnapura and Nuwara Eliya in a reducing pattern. IRI models forecast 25 mm of rainfall for the entire country. 

1 Month Prediction: Overall, from 15th-19th May 2012, rainfall shall increase drastically and then it shall decrease gradually till the 26th. There onwards rainfall shall increase gradually with minor fluctuation between 26th May-2nd June followed by a gradual increase till the 14th June. Western Slopes- A rapid increase of rainfall shall be expected duing 15th-19th May and reached to a peak on the 19th. During 19th May-2nd June rainfall shall decrease but there shall be minor peaks on 23rd and 28th May. There onwards ranfall shall increase. Eastern Slopes- Rainfall shall increase during 15th-18th May. Rainfall shall gradually decrease during 18th May-1st June and shall reach to the forcasted daily precipitation of 3 mm which is the lowest for the entire isalnd. There onwards rainfall shall increase drastically. Northern Region- Rainfall shall increase during 15th-19th and shall decrease till 25th May. Threafter rainfall shall increase gradually with low increasing rate. 
Seasonal Prediction: As per IRI Multi Model Probability Forecast for May 2012 to July 2012, issued in April 2012, there is a 40%-45% probability for temperature to be below normal particularly in the northern half of the country while 40% probability for it is to be normal in the southern half. There is 40% probability for rainfall to be climatological. 
International Research Institute for Climate and Society. 
2 These interpretations of hydro-meteorological conditions for the Mahaweli bas 
Inside this Issue 
1. Monitoring 
a. Daily Satellite Derived Rain fall Estimates 
b. Monthly Rain fall Estimates 
c. Decadal (10 Day) Satellite Derived Rainfall Estimates 
d. Weekly Average SST Anomalies 

2. Predictions 
a. NCEP GFS Ensemble 1-7 day predictions, NOAA, CPC,USA 
b. IMD WRF Model Forecast 
c. Weekly precipitation forecast (IRI) 
d. 1 month experimental predictions by Paul Roundy and L. Zubair 
e. Seasonal Predictions from IRI 

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