May 19, 2024

The El Niño phenomenon continues to weaken but its impacts – hotter and drier conditions – will continue to be felt in the Philippines until next month, even as the possible onset of La Niña is currently being closely monitored, according to a weather official.

Rusy Abastillas, senior weather specialist at the Pagasa, said in an online briefing that there have been signs of cooling across most of the equatorial Pacific Ocean over the last four weeks, indicating the weakening of El Niño.

But even as El Niño is waning, its effects will continue to be notable until May, Abastillas said in an update on April 25.

“There is about 95 percent probability this El Niño, although weak already, will continue until March-April-May season.”

She added Pagasa then expects the likely transition from El Niño to El Niño-Southern Oscillation (ENSO)-neutral – referring to those periods when neither El Niño nor La Niña is present – “from April, May, June up to May, June, and July, which is more than 70 percent probability.”

This will be followed by the increasing odds (at least 60 percent chance) of La Niña developing in the June, July to August 2024 season up to November, December, and January 2025, said Abastillas.

El Niño and La Niña represent opposite extremes in the naturally occurring climate cycle referred to as ENSO.

El Niño refers to a periodic weather event characterized by a warming of the ocean surface or above-average sea surface temperatures in the eastern equatorial Pacific. It is associated with droughts, heat waves, heavy rainfall, and other extreme weather events.

La Niña is usually associated with lower than normal air pressure, which brings above normal rainfall conditions.
However, Abastillas said historically, a pre-developing La Niña is characterized by below normal rainfall.

“Therefore the possibility of a slight delay in the onset of the rainy season is likely with the combined effects of the ongoing El Niño,” she said.

“So we still expect lower rainfall volume this coming rainy season,” she said.

Abastillas said they are expecting 10 to 13 tropical cyclones to enter or develop in the Philippine area of responsibility from May to October 2024.

She also gave updated forecasts on prevailing temperatures from May to October, noting that “below average to warmer than average surface air temperatures are expected throughout the country during the forecast period.”

Meanwhile, Miguel Adrian Garcia of the Philippine Disaster Resilience Foundation in his presentation said “we are facing extremes during this time of the ENSO phenomenon.”

He observed even as the El Niño phase has been weakening, “we’re still expecting above normal temperatures, and we’re still going to have dry spells and droughts all over the country.”

As El Niño transitions to La Niña, “we’re expecting below normal rainfall and delay of the onset of the rainy season, but with the decrease we are still expecting heavy rainfall during the habagat season,” he added.

He said above normal rainfall could come as early as October, coinciding with the peak of the tropical cyclone season.

Garcia also cited Pagasa’s forecast that the Philippines could be visited by 13 to 16 tropical cyclones up to the end of the year, which is less than the 19 to 20 cyclones on average. – Press release