Weekly Hydro-meteorological Report, 14 May, 2015

Highlights:


AA rainfall around 10 - 130mm rainfall was received throughout the week in entire country during 6 th May to 12 th May 2015. In the first two days of the week the rainfall was around 10-30mm and Kurunegala, Matale and Vavuniya districts received the highest rainfall of 130mm in the end of the week. The entire country received heavy rains on 10 th May and the heavy rains were gradually increased up to 30-40mm in northern region while the central and southern region of the country received the average rainfall of 10-20mm. NOAA predicts a continuation of high rainfall in Sri Lanka in the next two weeks.
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Summary

Monitoring


Weekly Monitoring:: During the time period 6 th May – 12 th May 2015, the rainfall was observed up to 30 mm/day which did not show a significant increase when compared to the past week. Throughout the week the whole country received an average rainfall up to 10-30 mm/day in all districts. In 10 th May, the whole country received a rainfall up to 30 mm/day while Central province and North central province received rainfall up to 130 mm/day. In 9 th and 11 th May, rainfall was received in the sea area up to 30 mm/day while the country received up to 20 mm/day. During the end of week, the heavy rainfall headed towards Northern Province while the rainfall was 40 mm/day and the highest rainfall was observed at Vavuniya, which was 130 mm/day. In the last days of week, the southern region of the country received rainfall up to 10 mm/day.


Monthly Monitoring: In April 2015 the entire country received above average rainfall except in Trincomalee, Batticaloa, Jaffna and Polonnaruwa districts and the northern regions of Ampara district.

Predictions

14-day prediction: NOAA NCEP models predict high rainfall up to 35 mm/day in the entire the country during the next fortnight.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, north, north east, north-west and western regions of country shall receive rainfall up to 35 mm and the rest of country shall receive light rainfall on 13 th May 15 th May. However the rainfall may increase up to 65mm on 16 th May on some areas of western region.

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 16, 2014 :During March through early April 2015 the SST met the threshold for weak Niño conditions. Most of the atmospheric variables now indicate an El Niño pattern, including weakened trade winds, low Southern Oscillation Index and excess rainfall in the vicinity of the dateline. The consensus of ENSO prediction models indicate weak El Niño conditions during the AprilJune 2015 season in progress, likely strengthening during summer and lasting through 2015
INDIAN OCEAN STATE :0.5 degrees C above average temperature was observed around Sri Lanka
MJO STATE :MJO continues to be weak and therefore shall not have a significant impact on the rainfall in Sri Lanka