More rain is expected in Singapore over the next few months despite it getting drier for the rest of September 2020.

La Nina detected

The wet weather ahead will be due to the arrival of La Nina.

La Nina-like conditions are descending upon the Southeast Asia region this month, early observations show.

More observations over the next several months will be needed to confirm La Nina's presence, but weathermen have since July been keeping an eye out for this climate phenomenon.

Conditions detected

However, the United States' National Oceanic and Atmospheric Administration (NOAA) has concluded that La Nina conditions are present.

These conditions include changes in the sea surface temperature, cloudiness, and winds in the tropical Pacific Ocean.

What is La Nina?

La Nina is the sister phenomenon of El Nino.

El Nino is usually associated with hot and dry weather in Southeast Asia.

La Nina and El Nino are opposite phases of a climate phenomenon called the El Nino Southern Oscillation.

El Nino vs La Nina

During an El Nino event, Southeast Asia as a whole receives less rain and hotter weather.

But during a La Nina event, the opposite happens.

Singapore's location

Singapore is situated in the western Pacific.

This location is between the Pacific Ocean, to the east, and the Indian Ocean, located to the west.

Why El Nino produces less rain & hotter weather

The western Pacific is much warmer than the east under normal conditions.

Predictable trade winds mainly blow from east to west.

Warm water is confined around the maritime continent where Singapore is located.

But trade winds weaken during El Nino and the warm water moves towards the central Pacific Ocean to the east.

The rain clouds follow, taking away rain and resulting in hotter weather.

Why La Nina brings more rain

During La Nina, the opposite happens.

Trade winds intensify, concentrating the moisture supply and stimulates rain clouds formation over the maritime continent.

El Nino and La Nina are caused by changes in atmospheric pressure and sea surface temperatures in the tropical Pacific Ocean.

Heavy rains so far not due to La Nina -- yet

But the rainfall experienced in the first half of September is not likely to have been influenced by La Nina, The Straits Times reported, quoting weather scientist Koh Tieh Yong from the Singapore University of Social Sciences (SUSS).

Instead, the increased rainfall is likely due to the stronger winds blowing from the tropical Indian Ocean, which caused more rain clouds to form over South-east Asia, bringing more rain.

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