Weekly Hydro-meteorological Report, 13 August, 2015

Highlights:


Significant amount of rainfall was only observed in south western region of the country on the 8th. Other than that the rest of the country did not receive much rainfall. Dry conditions were observed in the northern region of the country. In the next two weeks high rainfall is not expected in any part of the country. However there shall be light rainfall in most parts of the country.
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Summary

Monitoring


Weekly Monitoring:During the time period 5th August – 11th August 2015, only light rainfall was observed throughout the country except on the 8th of August where up to 40 mm rain was observed. Other than that only less than 10 mm rainfall was observed in the country particularly in central and south western regions of the country. No rainfall was observed in northern regions of the country during 5th – 11th. Sea to the south of Sri Lanka received relatively higher rainfall during this period.


Monthly Monitoring:: In the month July 2015, south western region of the country received above average rainfall of up to 6 mm/day. The rest of the country received below average rainfall during this month.

Predictions

14-day prediction: NOAA NCEP models predict rainfall in south western region of the country during 12th – 25th August. During the first week, south western region shall receive rainfall up to 45 mm. The Jaffna peninsula shall receive up to 45 mm rainfall in the following week.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model Western region of the country shall receive rainfall up to 35 mm on 14th August and the eastern regions around Ampara shall receive light rainfall. The same rainfall pattern shall continue on the 15th as well. IRI CFS model predicts up to 50 mm total 6 day rainfall on the northern, north eastern, eastern, central and south western regions of the country during 12th- 17th August 2015. During this period there shall not be any heavy rainfall events in any part of the country.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for July to September, the total 3 month precipitation has a 40% chance of being below average. The 3 month temperature has more than 70-80% likelihood in the entire country of being in the above-normal tercile during this period.

PACIFIC SEAS STATE July 16, 2015 :During late June through mid-July 2015 the SST was at a moderate El Niño level. All atmospheric variables support the El Niño pattern, including weakened trade winds and excess rainfall in the east-central tropical Pacific. The consensus of ENSO prediction models indicate continuation of moderate, and likely becoming strong, El Niño conditions during the July-September 2015 season in progress. Further strengthening between summer and fall is likely, with the event lasting into early 2016.
INDIAN OCEAN STATE : 1 0C above average temperature was observed around Sri Lanka.
MJO STATE :MJO is weak and therefore shall not have a significant impact on the rainfall in Sri Lanka.