Weekly Hydro-meteorological Report, 26 September, 2013

Highlights

Monitoring and Prediction
Northern regions, specially the Jaffna district shall receive more rainfall compared to the entire country. However entire Island shall not observe significant rainfall events during coming week (27th September-3rd October).

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Summary

Monitoring


Weekly Monitoring:During 17th-24th September 2013, rainfall ranged 5-20 mm. More rainfall observed during 17th & 18th for Jaffna and Gampaha districts. Rest of the days was dry.


Monthly Monitoring:Central and Northern provinces received an above average rainfall during the month of August.

Predictions

7-day prediction:South-western regions shall receive 5-55 mm of rainfall and Northern regions shall receive 5-45 mm of rainfall during 25th September-1st October 2013.

IMD WRF Model Forecast & IRI forecast:For 27th & 29th of September, IMD WRF model predicts no rainfall for the entire country. NOAA model predicts high rainfall (25-50 mm/week) for Jaffna peninsula during 24th-29th September.

1 Month Prediction:Overall- Rainfall is not predicted till 4th of October 2013. Western Slopes – Rainfall shall vary between 0-2 mm/day during 26th September-11th October, except for 29th September-1st October, which shall receive rainfall of 2-4 mm/day. Western Coast – Rainfall is not predicted till 14th of October 2013. Slight rainfall is likely to observe during 30th September-1st October. Eastern Slopes– Rainfall is not predicted till 10th of October 2013. Slight rainfall is likely to observe during 4th-6th October. Eastern Coast – Rainfall is not predicted during 26th-30th September and 2nd-4th October. Rainfall shall increase drastically during 4th-6th October and shall decrease thereafter. Northern region- Rainfall is not predicted till 4th of October 2013. Slight rainfall is likely to observe during 4th-8th October. Southern Region- Rainfall shall vary below 2 mm/day during 26th September-7th October, except for 27th-29th September, which rainfall is not predicted.

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 September 19, 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 15th-21st September 2013.
MJO STATE :MJO is at phase 5 and is entering to phase 6, which shall not influence Sri Lanka rainfall.