Weekly Hydro-meteorological Report, 19 December, 2013

Highlights

Monitoring and Prediction
Rainfall shall increase gradually after 21st of December 2013. However, Eastern and Central provinces are likely to experience significant heaviest rainfall during coming week 17th-23rd December 2013. For coming two days (18th & 19th December), Eastern and Central provinces are likely to observe heavy rainfall and dry conditions prevail towards North and Northwestern parts of the country.

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Summary

Monitoring


Weekly Monitoring:During 9th -14st December 2013, rainfall ranged 5-30 mm/day. Maximum rainfall observed on 14th December for Central province. Rest of the days received lower amount of rainfall compared to the end of the week.


Monthly Monitoring:Kurunegala district received highest average rainfall during the month of November 2013.

Predictions

7-day prediction:During 17th-23rd December 2013, entire Sri Lanka received rainfall above 85 mm. Rainfall is likely to decrease towards Northern region and Eastern provinces shall experience more than 135 mm of rainfall.

IMD WRF Model Forecast & IRI forecast: For 16th of December, IMD WRF model predicts less than 2.5 mm of rainfall for Southern, Eastern and Uva provinces and rest of the regions shall experience a dry period. For 19th of December, IMD WRF model predicts the same rainfall pattern over the country. NOAA model predicts the heaviest rainfall (more than 135 mm/week) for the Hambantota and Galle districts and shall decrease towards northwest direction during 17th-23rd December 2013.

1 Month Prediction:Overall- Rainfall shall decrease gradually till 21st of December. Western Slopes –Rainfall shall decrease gradually during 17th-21st December and it shall increase gradually thereafter. Western Coast –western coasts shall receive same magnitude of the rainfall as western slopes. Eastern Slopes– Rainfall shall decrease gradually till 23rd of December and gradually increase thereafter. Eastern Coast – The rainfall is not predicted till 22nd December and rainfall shall increase gradually thereafter. Northern region- The rainfall is not predicted till 22nd. Southern Region- The rainfall decreases till 22nd .

Seasonal Prediction::As per IRI Multi Model Probability Forecast issued on November 2013; for December 2013 to February 2014, there is a 50-60% probability for temperature to be above normal in the country while the rainfall is to be climatological.

PACIFIC SEAS STATE November 21, 2013 :During October through mid-November the observed ENSO conditions remained neutral. Most of the ENSO prediction models indicate a continuation of neutral ENSO into the first quarter of 2014. During northern spring and summer a warming tendency is seen in both dynamical and statistical models.

INDIAN OCEAN STATE :Southern sea of Sri Lanka showed +10C anomaly and rest of the seas around Sri Lanka showed neutral seas surface temperature during 8th-14th December 2013.
MJO STATE :MJO is entering phase 4 and is likely to enter phase 5 during next week.