Weekly Hydro-meteorological Report, 26 December, 2013

Highlights

Monitoring and Prediction
A decrease trend in rainfall observed over the country from 14th -23rd December. However, Eastern provinces are likely to experience significant rainfall during 28th and 29th December. The models predict dry conditions over the other parts of the country.

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Summary

Monitoring


Weekly Monitoring: During 15th December Eastern province got rainfall ranged 10-30 mm/day. Maximum rainfall observed on 15th December for Batticaloa, Polonnaruwa and some parts of Ampara district. Rest of the days received lower amount of rainfall compared to the beginning of the week.


Monthly Monitoring:Nuwara-Eliya, Ratnapura and Monaragala districts received highest average rainfall during the month of November 2013.

Predictions

7-day prediction:During 26th December-1st January 2014, entire Sri Lanka received rainfall below 5 mm.

IMD WRF Model Forecast & IRI forecast: For 28th of December, IMD WRF model predicts less than 7.5 mm of rainfall for Eastern and provinces and rest of the regions shall remain dry. For 29th of December, IMD WRF model predicts less than7.5 mm of rainfall for Western and central province. IRI model predicts dry condition over the country.

1 Month Prediction:Overall- Rainfall shall decrease gradually till 30th of December. Western Slopes –Rainfall shall decrease gradually during 25th-30th December and it shall decrease gradually thereafter. Western Coast – Rainfall shall vary below 4 mm/day till 30th December. Eastern Slopes– Rainfall shall decrease gradually till 30th of December below 2mm/day. Eastern Coast – The rainfall is not predicted from 27th December to 3rd January.. Thereafter it shall decrease. Northern region- The rainfall decreases and rainfall is not predicted between 27th December to 3rd January. Southern Region- The rainfall is likely increasing between 2-6 mm/day till 30th December.

Seasonal Prediction::As per IRI Multi Model Probability Forecast issued on November 2013; for December 2013 to February 2014, 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 December 19, 2013 :During November through early December the observed ENSO conditions remained neutral. Most of the ENSO prediction models indicate a continuation of neutral ENSO into early 2014.. During northern spring and Summer a warming tendency is seen in both dynamical and statistical models.

INDIAN OCEAN STATE :Southern sea of Sri Lanka showed +10C anomaly and rest of the seas around Sri Lanka showed neutral seas surface temperature during 24th-30th November 2013.
MJO STATE :MJO is entering phase 3 and is likely to enter phase 4 during next week. This phenomenon shall influence Sri Lanka rainfall this week.