Weekly Hydro-meteorological Report, 09 April, 2015

Highlights


Heavy rainfall continued during the previous week with the highest rainfall observed in Puttalam and Kurunegala. Rainfall shall continue in the next week with more rainfall on the western side of the country. IMD WRF model predict heavy rainfall in the next two days while the NOAA NCEP model predicts a low amount of precipitation in the next 14 days.
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Summary

Monitoring


Weekly Monitoring::Heavy rainfall reaching up to 120 mm was observed in Puttalam and Kurunegala districts on the 31 st of March. On the 1 st of April rainfall decreased down to 30 mm in north-western Sri Lanka but increased up to 50 mm in western and Sabaragamuwa provinces. Up to 30 mm rainfall was observed in the entire country on the 2 nd and light rainfall on the 3 rd . No rainfall was observed on 4 th and 5 th of April and once again up to 30 mm rainfall was observed in Colombo, Gampaha, Kegalle and Ratnapura districts on the 6 th


Monthly Monitoring: In March 2015 the western side of the country received above average rainfall averaging up to 12 mm/day while the rest of the country received below average rainfall.

Predictions

14-day prediction: NOAA NCEP models predict less than 25 mm total rainfall in next two weeks.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, the south western and western regions of the country shall receive up to 35 mm rainfall on the 11 th & 12 th April. On the 11 th the rainfall in Galle and Ratnapura districts may go up to 65 mm and on the 12 th the rainfall in Kurunegala District shall receive heavy rainfall up to 125 mm. NOAA models predict up to 100 mm rainfall in the central mountain.

Seasonal Prediction: As per IRI Multi Model Probability Forecast for April to June, the total 3 month precipitation shall be climatological. The 3 month average temperature has more than 60- 70% likelihood of being in the above-normal tercile during this period.

PACIFIC SEAS STATE April 9, 2014 :During March through earlyApril 2015 the SST just met the thresholds for weak Niño conditions. Some of the atmospheric variables began indicating an El Niño pattern more than they had been earlier, including trade wind weakening and excess rainfall migrating farther to the east. The consensus of ENSO prediction models indicate weak El Niño conditions during the March-May 2015 season in progress, continuing and strengthening El Niño toward mid-2015
INDIAN OCEAN STATE :Neutral sea surface temperature was observed in the sea around Sri Lanka.
MJO STATE :MJO is in phase 3 and therefore shall enhance rainfall in Sri Lanka