Weekly Hydro-meteorological Report, 14 February 2013

Highlights

Monitoring and Prediction
Significant amount of rainfall is predicted for Southern regions of Sri Lanka for the coming week. For 15th & 16th February, 2013 Ratnapura and Kegalle districts shall receive a considerable amount of rainfall. However rainfall shall decrease gradually till 22nd for entire Sri Lanka.

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Summary

Monitoring


Weekly Monitoring:During the period 6th-12th February 2013 rainfall ranged between 5-185 mm. Maximum amount of rainfall was observed on the 12th February in Trincomalee & Mulativu districts. From 29th January-2nd February most of the regions experienced a wet condition. On 11th & 12th the entire country received rainfall.

Predictions

7-day prediction:Considerable amount of rainfall (5-55 mm) is predicted for the period of 13th-19th February 2013 for central mountainous regions and upper most regions of Northern Sri Lanka.

IMD WRF Model Forecast & IRI forecast:For the 15th of February 2013, IMD WRF model predicts less than 65 mm of rainfall for the district boundary region between Ratnapura & Kegalle districts. For the same day rest of the regions shall receive rainfall less than 36 mm. For the 16th of February, IMD WRF model prediction indicates that rainfall shall shift towards the west direction which shall receive less than 36 mm of rainfall for Puttalam, Kandy, Nuwara Eliya, Badulla, Ratnapura, Kegalle and Gampaha and, shall reduce in the adjoining regions. For the same day less than 1 mm of rainfall is predicted for the Northern and Eastern districts of Sri Lanka. NOAA model predicts heavy rainfall for the Southern 1/3rd of the country from 13th– 18th February.

1 Month Prediction: Overall-Existing rainfall shall persist till 22nd February. Thereafter rainfall shall increase. Western Slopes – Existing rainfall shall persist till 19th February, and shall decrease to reach minimum rainfall on 22nd February for the period between 12th February-9th March. Thereafter rainfall shall increase. Western Coast - Existing rainfall shall persist till 16th and shall decrease till 21st. Thereafter rainfall shall increase. Eastern slopes - Rainfall shall vary frequently, but not significantly. However after 22nd rainfall shall increase significantly. Eastern Coast - Rainfall is not predicted for 13th-16th February. Thereon rainfall shall be observed same as in the Eastern slopes. Northern region- Rainfall shall decrease till 18th upto 0 mm/day. Thereafter rainfall shall gradually increase. Southern Region- Existing rainfall shall persist till 15th & it shall reduce drastically till 17th. Thereafter it shall increase gradually.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued on January 2013; for February 2013 to April 2013, 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 February 7, 2013 :Most of the ENSO prediction models predict natural ENSO conditions through the first half of 2013. During January the observed SST conditions have become below average, but in the neutral range.

INDIAN OCEAN STATE :In the Pacific, the El Nino state has weakened to neutral although there is weak warming remnant in the El Nino index areas. The unusually warmer sea surfaces of the Arabian Sea/Central Western and South-Eastern Indian Ocean remain.