Weekly Hydro-meteorological Report, 17 October, 2013

Highlights

Monitoring and Prediction
Heavy rainfall is likely to observe for Batticaloa, Galle-Gampaha and parts of Anuradhapura districts during coming two days (18th & 19th October). South-western regions shall receive heavy rainfall during 16th-22nd October 2013.

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Summary

Monitoring


Weekly Monitoring:During 8th-14th October 2013, rainfall ranged less than 40 mm/day. Northern regions received more rainfall compared to the rest of the island. However, the island was comparatively drier than the previous months.


Monthly Monitoring:Jaffna and Batticaloa districts received an above average rainfall during the month of September.

Predictions

7-day prediction:Galle and Kalutara districts shall receive heavy rainfall (more than 135 mm/day) and shall spread towards North, North-east and East directions in a reducing pattern during 16th-22nd October 2013.

IMD WRF Model Forecast & IRI forecast:For 18th of October, IMD WRF model predicts less than 65 mm of rainfall for coastal regions of Batticaoloa and Galle-Kalutara districts. For the same day rest of the regions shall receive less than 36 mm/day, except for the parts of Hambantota. For 19th of October, model predicts less than 65 mm/day of rainfall for coastal regions of Galle-Gampaha, Batticaloa and parts of Anuradhapura. For the same day rest of the regions shall receive less than 36 mm/day of rainfall. However, NOAA model prediction is suspended this week due to the U.S. Government shutdown.

1 Month Prediction:Overall- Rainfall is likely to increase gradually till 26th October. Western Slopes – The rainfall pattern persisting in the entire country shall be observed in this region. Western Coast – The rainfall pattern persisting in the entire country shall be observed in this region. Eastern Slopes– Rainfall shall decrease gradually till 22nd and is likely to increase thereafter. Eastern Coast – The rainfall pattern persisting in the Eastern slopes shall be observed in this region. However, rainfall is not predicted during 20th-24th October. Northern region- The rainfall pattern persisting in the Eastern slopes shall be observed in this region. Southern Region- The rainfall pattern persisting in the Eastern slopes shall be observed in this region

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued on September 2013; for October 2013 to December 2013, there is a 60-70% probability for temperature to be above normal in the country while the rainfall is to be climatological.

PACIFIC SEAS STATE July 18, 2013 :During August through early September the observed ENSO conditions remained neutral. Most of the ENSO prediction models indicate a continuation of neutral ENSO through 2013 & the first quarter of 2014. However, a few (mainly statistical) models call for cooling towards borderline or weak La-Nina conditions for northern autumn into winter, while a few others (mainly dynamical) forecast a warming toward borderline or weak El-Nino conditions for this same time frame.

INDIAN OCEAN STATE :The sea surface temperature around Sri Lanka was neutral during 6th-12th October 2013.
MJO STATE :MJO is neutral and not influences Sri Lanka rainfall.