Weekly Hydro-meteorological Report, 12 February, 2015

Highlights

Monitoring and Prediction

As predicted earlier by NOAA NCEP models, there has been rainfall since the end of January in various parts of the country. Based on IRI models, during 11 th to 16 th eastern, uva, sabaragamuwa, central and southern regions shall receive rainfall averaging up to 50 mm with highest expected rainfall in Badulla area averaging up to 75 mm. But NOAA NCEP models have provided a contradictory prediction which says that there shall be no rainfall during the next week and the week after. The sea around Sri Lanka continue to show neutral sea surface temperature.
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Summary

Monitoring


Weekly Monitoring::Not Available this week.


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 Sri Lanka shall not receive rainfall during 11 th to 17 th February. According to the model dry condition shall persist further between 18 th to 24 th February.

IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model, on 13 th February heavy showers can be expected in Batticaloa and surrounding areas up to 125 mm in magnitude. Galle, Colombo and Hattton areas shall receive rainfall around 65 mm with the rest of the country receiving an average of 2 mm to 8 mm on the same day. Similar condition can be expected on 14 th February, however rainfall is not expected in northern region on that day. IRI model predicts that during 11 th to 16 th February eastern, uva, sabaragamuwa, central and southern regions shall receive rainfall up to 50 mm with highest rainfall in Badulla area averaging up to 75 mm. But heavy rainfall events are not likely during these six days.

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 8 in the Western Hemisphere and therefore shall slightly enhance the rainfall in Sri Lanka