Weekly Hydro-meteorological Report, 5 November, 2014

Highlights

Monitoring and Prediction

Very heavy rainfall was observed throughout the country and mostly around the south-west and central regions during the previous week and rainfall shall decrease significantly in the entire country during next week. The entire sea region of Sri Lanka shows a neutral sea surface temperature.
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Summary

Monitoring


Weekly Monitoring::From 28th of October to 30th of October high rainfall was observed throughout the country averaging up to 60 mm specially in central, south-west and south-east regions. On 31st of October rainfall in the entire country has decreased significantly with no or minor rain in random regions. From 1st of November to 3rd of November high rainfall was observed again around the north-east area averaging around 30 mm in general.


Monthly Monitoring:An average rainfall of 14 mm-16 mm was observed throughout the country with higher precipitation observed in the south-western regions of Sri Lanka during October. Highest rainfall during this month was observed in Uva, Sabaragamuwa and Central provinces. Also the decadal rainfall average was around 14 mm-18 mm.

Predictions

14-day prediction:The entire country shall receive total rainfall around 35 mm during 4th of November to 10th of November. Rainfall is expected to increase in the south-west region during 11th November to 17th November resulting in very high rainfall of more than 125 mm in total.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model the north-western, western and south-western regions shall receive high rainfall around 7.5 mm on 6th of November. By 7th of November rainfall shall decrease in the entire country with only 2.5 mm average in the west coast. Light rainfall is expected during 4th – 9th November throughout the country with around 25 mm in average.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued in October for the season November 2014 to January 2015, Rainfall shall remain climatological while the temperature shall be above normal with a high probability.

PACIFIC SEAS STATE October 16, 2014 :During September through early October the observed ENSO conditions retreated from those of a borderline El Niño to a warmish ENSO-neutral state. However, most of the ENSO prediction models continue to indicate development of weak El Niño conditions during the October-December season in progress, peaking at weak strength during winter 2014-15 and lasting through most of northern spring 2015.
INDIAN OCEAN STATE :The sea surface temperature was neutral around the entire coast of the country.
MJO STATE :MJO is weak and therefore it shall not have any influence on rainfall in Sri Lanka.