Weekly Hydro-meteorological Report, 26 February, 2015

Highlights


In previous week significant rainfall was observed during 22 nd to 24 th in all most all parts of the country. Highest rainfall for the week was observed on 23 rd in Tricomalee area around 95 mm. Rainfall is expected to increase during 26 th February to 3 rd March for the entire country and further during 4 th to 10 th March.
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Summary

Monitoring


Weekly Monitoring:: More or less no rainfall was observed during 18 th to 20 th February. On the 21 st rainfall was observed along the eastern coast averaging up to 10 mm. On 22 nd Mahiyangana area received rainfall around 20 mm and Batticaloa, Ampara, Badulla,Nuawara Eliya, Ratnapura, Colombo received about 10 mm each. On the 23 rd Trincomalee received the highest amount of rainfall of 95 mm while areas around in Kalutara, Batticaloa, Amapra received 30 mm each and north central, central, and eastern regions received rainfall around 10 mm. On 24 th Batticaloa and Kegalle received rainfall around 30 mm and central, north western, north central received rainfall around 10 mm each.


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. Rainfall received in the month was observed to be below average. Decadal rainfall average was decreased during 11 th to 20 th February compared to 1 st to 10 th February.

Predictions

14-day prediction: NOAA NCEP models predict entire country shall receive rainfall during 25 th February to 3 rd March exceeding 25 mm and rainfall is expected to increase during 4 th to 10 th March exceeding 35 mm.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, entire country shall receive rainfall on 27 th February with high precipitation around 65 mm in north-western, central and sabaragamuwa areas. Heavy rainfall shall continue in sabaragamuwa, central and southern areas on 28 th February. IRI model predicts that during 25 th February to 2 nd March an average rainfall of 75 mm can be expected in areas around Nuwra Eliya, Badulla and Ratnapura.

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 19, 2014 :During January through early February 2015 the SST just met the thresholds for weak Niño conditions. Lately some of the atmospheric variables began indicating an El Niño pattern a little more than they had been before January. The consensus of ENSO prediction models indicate warm neutral to borderline El Niño conditions during the February-April season in progress, continuing into northern spring 2015, with some suggestion of strengthening El Niño toward mid-2015.
INDIAN OCEAN STATE :Neutral SST was observed in the sea around Sri Lanka.
MJO STATE :MJO is in the phase 7 of the Western Pacific ocean therefore it shall slightly suppress rainfall in Sri Lanka.