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Wednesday, December 11, 2013

Weekly Hydro-meteorological Report, 04 December, 2013


Monitoring and Prediction
Rainfall shall increase gradually till 13th of December 2013. However, Northern, North-central, Eastern and Central provinces are likely to experience significant heaviest rainfall during coming week (5th-12th December 2013). For coming two days (5th & 6th December), Northern, North-central, Eastern and Central provinces are likely to observe heavy rainfall and rainfall shall spread towards Southwestern direction in a reducing manner.

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Weekly Monitoring: During 25th November-1st December 2013, rainfall ranged 5-125 mm/day. Maximum rainfall observed on 25th November for Moneragala district. Rest of the days received lower amount of rainfall compared to the beginning of the week.

Monthly Monitoring: Kurunegala district received highest average rainfall during the month of October 2013.


7-day prediction:During 3rd-9th December 2013, entire Sri Lanka received rainfall above 85 mm. Rainfall is likely to spread towards Northern region in an increasing pattern and Northern, North-central and Eastern provinces shall experience more than 135 mm of rainfall.

IMD WRF Model Forecast & IRI forecast: For 5th of December, IMD WRF model predicts less than 125 mm of rainfall for Northern, North-central, Eastern and Central provinces and rest of the regions shall receive less than 8 mm of rainfall. For 6th of December, IMD WRF model predicts less than 125 mm of rainfall for Northern province and rainfall shall spread towards down south of Sri Lanka in a reducing pattern. NOAA model predicts the heaviest rainfall (more than 300 mm/week) for the boarder of Mullaitivu and Trincomalee districts and shall spread towards southwest direction in a reducing manner during 3rd-8th December 2013.

1 Month Prediction:Overall- Rainfall shall increase gradually till 13th of December. Western Slopes –Rainfall shall increase gradually during 3rd-10th December and it shall decrease gradually thereafter. Western Coast – Rainfall shall vary below 12 mm/day till 13th December. However, western slopes and western coasts shall receive same magnitude of the rainfall. Eastern Slopes– Rainfall shall increase gradually till 11th of December and decrease thereafter. Eastern Coast – The rainfall is not predicted till 10th December and rainfall shall increase gradually till 12th. Thereafter it shall decrease. Northern region- Constant amount of rainfall is likely to observe for this region till 13th December. Southern Region- The rainfall is likely to vary between 2-5 mm/day till 20th 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 November 21, 2013 :During October through mid-November the observed ENSO conditions remained neutral. Most of the ENSO prediction models indicate a continuation of neutral ENSO into the first quarter of 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 +1 degree Celsius anomaly and rest of the seas around Sri Lanka showed neutral seas surface temperature during 24th to 30th November 2013.
MJO STATE :MJO is entering phase 2 and is likely to enter phase 3 during next week. This phenomenon shall influence Sri Lanka rainfall.

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