The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) has upgraded the La Niña Watch to a La Niña Alert, which means La Niña is highly likely to form before the end of 2021.
PAGASA Administrator Dr. Vicente Malano said their recent climate monitoring and analyses have indicated that La Niña may emerge in the coming months.
"Based on the latest forecasts mostly from climate models and expert judgments, there is a 70 percent to 80 percent chance that the La Niña will form in the 4th quarter of 2021 and may persist until the first quarter of 2022," Malano said in a statement on Monday, Sept. 13.
La Niña is characterized by unusually cool ocean surface temperatures in the central and eastern equatorial Pacific.
Malano noted that rainfall forecasts suggest a "higher probability of above-normal rainfall conditions in many areas of the country in the next several months."
"This can be attributed to the expected stronger easterlies, enhanced northeast monsoon and tropical cyclone occurrences," he said.
"Furthermore, the eastern sections of the country, which normally receive more rainfall during the last quarter of the year, could further increase the likelihood of more adverse impacts such as floods and landslides over highly vulnerable areas," he pointed out.
Malano advised concerned agencies to take the necessary precautionary measures to mitigate the potential adverse impact of the looming La Niña.
PAGASA said it will closely monitor these conditions and regular updates and advisories will be issued as appropriate.
A La Niña Watch was first issued by PAGASA on July 16, 2021, before it was upgraded to a La Niña Alert on Sept. 13, 2021.
If La Niña develops later this year, it will be a back-to-back event as the 2020-2021 La Niña only ended in June 2021.
PAGASA's Climate Monitoring and Prediction Section chief Ana Liza Solis said during the climate outlook forum in August that back-to-back La Niña episodes are not unusual, noting that the last six episodes occurred back-to-back.
These were in 2007-2008 and 2008-2009; 2010-2011 and 2011-2012; and 2016-2017 and 2017-2018.