Weekly Hydro-meteorological Report, 5 February, 2015

Highlights

Monitoring and Prediction

Roughly entire country received rainfall during the past week averaging up to 20 mm. Some rainfall can be further expected between 6 th to 10 th February but thereafter a dry condition can be expected all over the country.
Download Full Report




Summary

Monitoring


Weekly Monitoring::On 28 th rainfall was observed in western and south-west regions of the country averaging up to 10 mm. On 29 th heavy rainfall was observed in Colombo and Kalutara areas around 30 mm while central and southern regions also received rainfall around 10mm. On the 31 st Ratnapura area received rainfall around 30 mm and during 1 st to 2 nd February Moneragala and Badulla areas received heavy rainfalls around 30 mm. On 3 rd entire country received rainfall averaging up to 10 mm with higher precipitation in north-eastern coast of the island averaging around 50 mm.


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 areas 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 the entire country shall receive rainfall during 4 th to 10 th February exceeding 35 mm. Rainfall is expected to cease during 11 th to 17 th February.

IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model, on 6 th February rainfall can be observed in most parts of the country except Hambantota. On that day central and eastern regions shall receive rainfall around 35 mm. Rainfall is expected to decrease on 7 th February but Galle and Ratnapura areas shall receive rainfall around 35 mm. IRI model predicts that rainfall can be expected in southern,western,eastern and central regions of the island during 4 th to 9 th February.

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 January 15, 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 in phase 7 therefore shall slightly suppress rainfall in Sri Lanka.