Weekly Hydro-meteorological Report, 19 February, 2015

Highlights


During past week significant rainfall was only observed between 11 th to 13 th in western, southern, eastern and central areas averaging up to 10 mm. Highest rainfall for the week was observed on 12 th February in Ratnapura around 60 mm. During 18 th to 23 th rainfall can be observed in northern and western areas.
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Summary

Monitoring


Weekly Monitoring:: On 11 th rainfall was observed in western, southern, eastern and central regions of the country averaging up to 20 mm with high rainfall in Avissawella and Kataragama areas averaging up to 40 mm. On 12 th areas around Avissawella and Ratnapura received rainfall averaging up to 50 mm. Rainfall decreased on 13 th but still significant rainfall was observed in Sabaragamuwa, western and eastern regions of the island averaging up to 20 mm. Some rainfall was observed in Galle and Matara areas on 14 th . Thereafter rainfall was completely ceased during 15 th to 17 th February.


Monthly Monitoring: During January an average rainfall of 2 mm to 5 mm was observed in western, southern, sabaragamuwa and uva regions. Highest rainfall in January was observed in the areas of Kalutara and Ratnapura. Decadal rainfall average was slightly increased during 21 st to 31 st January compared with 11 th to 20 th January.

Predictions

14-day prediction:NOAA NCEP models predict that northern region shall receive rainfall during 8 th to 24 th February exceeding 35 mm. According to the model rainfall is expected to cease during 25 th February - 3 rd March.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, no significant rainfall is expected on the 20 th and 21 st of February. According to IRI model, during 18 th -23 th February Colombo area shall receive 6 day total rainfall around 50 mm.

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

PACIFIC SEAS STATE February 5, 2014 :During December 2014 through early January 2015 the SST exceeded thresholds for weak Niño conditions, although only some of the atmospheric variables indicate an El Niño pattern. Most of the ENSO prediction models indicate weak El Niño conditions during the December-February season in progress, continuing through most or all of northern spring 2015.
INDIAN OCEAN STATE :Neutral SST was observed in the sea around Sri Lanka.
MJO STATE :MJO is weak therefore it shall not affect the rainfall in Sri Lanka