Drier, warmer months ahead with higher chance of haze

AS IF it is not hot and dry enough now, the coming months are also expected to be drier and warmer than usual.

This is a result of the strengthening El Nino phenomenon, which will also increase the risk of transboundary haze here, said the National Environment Agency (NEA) in a release yesterday.

Singapore has been warmer and drier than average this month. Total rainfall for this month, up to Thursday, was 38 per cent below the long-term average.

Average daily maximum and minimum temperatures were 31.9 and 26.5 deg C - about 0.6 and 1.7 deg C above the long-term average respectively.

Dry weather is likely to persist, with the Meteorological Service Singapore forecasting lower than usual rainfall for the next few months.

The total monthly rainfall for next month is predicted to be 15 to 45 per cent below average.

In 1997, when the El Nino was the strongest on record, Singapore's rainfall from June to September was only about half the usual average.

The service also said there may be an escalation of hotspot activities - brought about by forest and plantation fires - particularly in fire-prone provinces in Sumatra and Kalimantan.

"In recent days, sporadic hotspot activities with localised smoke plumes have been observed in Sumatra," it said.

Assistant Professor Adam Switzer, a principal investigator at the Nanyang Technological University's Earth Observatory of Singapore, said drier conditions increase the likelihood of forest fires in the region and hence the chances of haze in Singapore.

But he added: "Though I must emphasise that drier conditions are not the only factor at play here and the local wind conditions also need to be right to bring haze to Singapore."

But whether there would be haze here also depended on the proximity and extent of the fires and the incidence and amount of rain, NEA said.

The drier and warmer weather signals the start of the traditional dry season in southern Asean, which is triggered by the El Nino phenomenon.

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

Most major global climate centres project a further warming of the tropical Pacific sea surface temperatures in the months ahead, which could lead to a strong El Nino.

Assistant Professor Winston Chow, of the National University of Singapore's department of geography, said the US National Oceanic and Atmospheric Administration has indicated that there is a high chance that El Nino will last until December, or even February or March next year.

samboh@sph.com.sg

A version of this article appeared in the print edition of The Straits Times on June 27, 2015, with the headline 'Drier, warmer months ahead with higher chance of haze'. Print Edition | Subscribe