The chance of a La Niña forming as early as September has increased to 60 percent.
This could mean a higher chance of tropical cyclone development and above normal rainfall conditions in most of the country from late 2020 to early 2021.
According to Ana Liza Solis, chief of the Climate Monitoring and Prediction Section of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), a La Niña Watch has been first issued in July with the climate seemingly favoring the condition with a probability of “55 percent or more.”
Solis explained the La Niña Watch will be upgraded to a La Niña Alert if the probability increases to 70 percent or more and if oceanic indicators persist in the next two months.
“Kapag tumaas pa sa 70 percent (ang probability) by September, maglalabas na ng La Niña Alert ang PAGASA para sa maagang action mula sa affected na sectors. (If the probability increases to 70 percent by September, a La Niña Alert will be issued by PAGASA for early action from the affected sectors),” Solis said during PAGASA’s monthly climate outlook forum on Wednesday.
She noted current key oceanic and atmospheric indicators are consistent with a developing La Niña in late September to October, which may last through February 2021.
Solis pointed out that the looming La Niña may have a significant impact on the rainfall in Luzon by December, and Mindanao by January until February.
Generally above normal rainfall conditions will be likely in Luzon, and near to above normal in the Visayas and Mindanao in December 2020.
By January 2020, rainfall conditions will likely be below normal in Ilocos Region and Central Luzon, while it will be near to above normal in most areas in Southern and eastern Luzon, and generally above normal in Visayas and Mindanao.
By February 2020, PAGASA predicts generally near to above normal rainfall conditions over most parts of Luzon, whole of Visayas and Mindanao, while way below to below normal rainfall will be likely in the Cordillera Administrative Region and Ilocos Region.
“Kung di magbabago ang condition sa tropical Pacific ito ang impact sa ating ulan kaya kailangan paghandaan. (If the conditions in the tropical Pacific do not change, these will impact our rainfall so we need to prepare.),” Solis said.
She added that the developing La Niña may also bring a significant impact on the country’s tropical cyclone activity.
Based on the PAGASA’s historical record, there is only a slim chance that tropical cyclones form in January to February. But due to the looming La Niña, there is a likelihood that one to three cyclones may develop during these months, she said.