Weekly Hydro-meteorological Report, 24 April, 2013

Highlights

Monitoring and Prediction
Northern regions of the island shall receive rainfall for the coming two days (25th and 26th April 2013) and North-eastern regions of the island shall receive rainfall during 23rd-29th April. Existing rainfall condition shall increasing with slight variation around 29th April and western slopes shall receive more rainfall. During May 2013 to July 2013, there is a 45-50% probability for temperature to be above normal in the country while the rainfall is to be climatological.

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Summary

Monitoring


Weekly Monitoring:Rainfall ranged between 5-55 mm during 16th-22nd April 2013. Maximum rainfall was observed on the 22nd April in Moneragala district. During 16th-21st almost entire Island received low rainfall compared to 22nd April.

Predictions

7-day prediction:North-eastern 2/3rd of the Island shall receive 5-55 mm of rainfall during 23rd-29th April.

IMD WRF Model Forecast & IRI forecast:For 25th of April 2013, IMD WRF model predicts less than 8 mm of rainfall for Northern Province and 8-36 mm for the Islets of Jaffna peninsula. Rainfall is not predicted for the rest of the regions. Then for the 26th of April, IMD WRF model predicts less than 3 mm of rainfall for Mannar district. NOAA model predicts similar rainfall condition (less than 25 mm) for the entire country during 23rd-28th April.

1 Month Prediction:Overall-Existing rainfall condition shall increasing with slight variation around 29th April. Western Slopes – The rainfall pattern existing in the island shall be present in this region with increase amount of rainfall. Western Coast – Existing rainfall condition shall reduces till 29th April and it shall increase thereon. Eastern slopes – Existing rainfall condition shall vary during 24th-30th April and it shall increase thereafter. Eastern Coast – Rainfall is not predicted till 1st of May. Northern region- Rainfall shall increase with different rates. Southern Region- Rainfall shall vary between 1-3 mm of daily rainfall for the period of 24th April-4th May 2013.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued on April 2013; for May 2013 to July 2013, there is a 45-50% probability for temperature to be above normal in the country while the rainfall is to be climatological.

PACIFIC SEAS STATE April 18, 2013 :During February through March the observed ENSO conditions remained in the neutral ENSO conditions. Most of the ENSO prediction models call for neutral ENSO conditions through northern summer 2013, but some statistical models call for weak La-Nina while some dynamical models call for warming & possible weak El-Nino.

INDIAN OCEAN STATE :The Indian Ocean around Sri Lanka particular to the Bay of Bengal continues to have a warm anomaly up to 0.5˚C. Warm SST conditions are spreading towards seas north of Sri Lanka.