Expect hotter and drier months ahead

SINGAPORE - Get ready for hotter and drier days than usual over the next four months, with an increased likelihood of haze as well.

The El Nino weather phenomenon, involving abnormal warming of the tropical Pacific Ocean, is to blame, said the Meteorological Service Singapore (MSS) yesterday. Average daily temperatures are expected to be 1 deg C hotter than the long-term averages of 27.2-27.7 deg C for those months.

Also, rainfall is expected to be 10 to 40 per cent less than the long-term averages, in a period that is already the region's traditional dry season.

"Prolonged drier and warmer conditions during an El Nino will increase the risk of the occurrence of transboundary smoke haze from land and forest fires in the region," said the MSS.

With the unfavourable forecast, national water agency PUB is strongly urging people and businesses to conserve water as reservoir levels will fall in the months head because of the hotter weather and decreased rainfall.

"PUB will have to ramp up its production of Newater and desalinated water to maintain reservoir stock and ensure water availability," it said.

The Inter-Agency Haze Task Force comprising 23 government agencies is on the alert, and the members are coordinating plans to prepare for haze.

The Ministry of Education, for example, will consider closing primary and secondary schools to students if air quality is expected to be "hazardous" the day after.

The Government has stockpiled 16 million N95 masks to ease any shortages. The MSS said it will "closely monitor conditions in the tropical Pacific that lead to the development of El Nino, as well as the regional weather and haze situation, and provide updates if necessary".

El Ninos occur every three to five years on average. Scientists believe they are caused by a combination of simultaneous atmospheric and oceanic factors such as weakening easterly winds.

During an El Nino, a warm pool of water in the western Pacific Ocean sloshes eastwards, triggering thunderstorms that move away from South-east Asia towards the United States and South America.

A "strong" El Nino in 1997 resulted in droughts in Indonesia and severe flooding along the west coast of South America.

Here in Singapore, rainfall for June to September that year was about half of the usual average.

This year's El Nino is not expected to be severe, but rather "weak to moderate". In 2009, during a moderate El Nino, rainfall for June to September was about 20 per cent below the long-term average, while temperatures were about 1.1 degrees warmer.

Experts said temperature increases on some days could exceed the projected 1 deg C rise in average temperatures.

"At the very least, the rise in temperatures will cause more thermal discomfort for people who spend time outdoors," said Assistant Professor Winston Chow from the National University of Singapore's Department of Geography.

zengkun@sph.com.sg

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This article was first published on May 31, 2014.
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