Weekly Hydro-meteorological Report, 14 November, 2013

Highlights

Monitoring and Prediction
Rainfall shall decrease gradually till 21st of November and shall increase gradually thereafter. However, eastern half of the island shall experience more rainfall compared to the rest of the island during coming week (14th-18th November 2013). Jaffna Peninsula shall receive heaviest rainfall during next few days (around 17th November).

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Summary

Monitoring


Weekly Monitoring: During 5th-12th November 2013, rainfall ranged 5-70 mm/day. However, entire country received less than 10 mm/day of rainfall throughout the week, except small region in Vavuniya district on 5th November.


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

Predictions

7-day prediction: During 12th-18th November 2013, South-eastern regions shall experience 5-55 mm of rainfall and shall spread towards central hills in an increasing pattern. For the same period Jaffna Peninsula shall receive rainfall of 55-85 mm.

IMD WRF Model Forecast & IRI forecast: For 17th of November, IMD WRF model predicts more than 125 mm of rainfall for the Jaffna Peninsula and less than 8 mm of rainfall for scattered parts of Northern half of the island. However, NOAA model predicts heavy rainfall for North-eastern regions of Sri Lanka during 11th -16th November 2013.

1 Month Prediction:Overall- Rainfall shall decrease gradually till 21st of November and shall increase gradually thereafter. Western Slopes – The rainfall pattern persisting in the entire country shall be observed in this region with high amount of rainfall. Western Coast – The rainfall pattern persisting in the entire country shall be observed in this region with high amount of rainfall. Eastern Slopes– The rainfall pattern persisting in the entire country shall be observed in this region with frequent variations of rainfall events. Eastern Coast – The rainfall pattern persisting in the entire country shall be observed in this region and thereafter rainfall is not predicted. Northern region- The rainfall shall remain constant during 14th-18th and thereafter the rainfall pattern persisting in the entire country shall be observed in this region. Southern Region- The rainfall pattern persisting in the entire country shall be observed in this region with frequent variations of rainfall events.

Seasonal Prediction: As per IRI Multi Model Probability Forecast issued on October 2013; for November, December 2013 to January 2014, 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 October 17, 2013 :During September through October 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. A long lasting mean disagreement between statistical and dynamical models (statistical leaning cooler, dynamical warmer) has diminished. The average forecast of all models indicates a gradual warming tendency during the first half of the 2014.

INDIAN OCEAN STATE :The sea surface temperature around Sri Lanka was neutral during 27th October-2nd November 2013.
MJO STATE :MJO was at 3rd phase on 8th November and presently moving to 4th phase which shall not influence Sri Lanka rainfall.