Sri Lanka’s key monsoon suppressed so far in 2019
ECONOMYNEXT – Sri Lanka’s South West monsoon has been suppressed so far in 2019 amid a mild El Niño effect related to sea temperature in the Pacific, despite a warmer Western Indian Ocean which usually brings more rainfall, an official said.
The South West monsoon usually gets established by the third week of May with rain falling on the Western slopes of the hill country. In early May Sri Lanka has received pre-monsoonal rain.
“The last week of May is usually when the actual monsoon rain starts," Shiromani Jayawardena, Deputy Director, (Research & International Affairs), Department of Meteorology told EconomyNext.com.
"Records of rainfall in May and June indicate that a reduction in rainfall in the mountain regions of Wet zone prevailed.
"Places like NuwaraEliya, the western slope of the Central hills, is a very important region for hydro power generation because hydro catchment reservoirs are located here.
“Less rain in these regions will effect power generation.”
In 2019, there is a mild warming of the Western Indian Ocean, which can increase the water content of monsoonal winds coming to Sri Lanka, known as a positive Indian Ocean Dipole effect, giving above normal rains.
When the Eastern Indian Ocean warms – which is called a negative Indian Ocean Dipole – there is more rain for Indonesia and Australia.
A positive IOD tends to give more rain to Sri Lanka while El Niño or a negative IOD tends to trigger droughts.
In July so far Sri Lanka has received below median rainfall
Currently Sri Lanka is experiencing a positive IOD and a mild El Niño situation, affecting the country’s monsoon patterns.
"If the positive dipole effect continues we can have more rain in October and November" she said
Sri Lanka’s also got below normal rainfall so far this year, but most of its rain comes during the North East monsoons. (Colombo/July11/2019)