Four weather systems are currently affecting the country, bringing widespread rains to many parts of Luzon, Visayas, and Mindanao, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said on Wednesday, December 17.

Weather specialist Loriedin De la Cruz-Galicia said the shear line, northeast monsoon (amihan), Intertropical Convergence Zone (ITCZ), and easterlies are all contributing to cloudy skies and rainfall, raising concerns over possible flooding and landslides.

“Apat na weather systems ang nakakaapekto ngayon sa bansa, lahat po iyon ay nagdudulot ng mga pag-ulan sa iba’t ibang bahagi ng ating kalupaan (Four weather systems are currently affecting the country, all of which are bringing rainfall to various parts of our land),” she said.

De la Cruz-Galicia explained that the shear line is formed by the convergence of winds from the northeast and eastern sections of the country, generating cloud formations that bring continuous rains.

“Inaasahan natin na maghapon iyang magdudulot ng pag-ulan sa silangang bahagi ng Northern and Central Luzon at ilang bahagi din ng Southern Luzon (We expect that throughout the day it will bring rainfall to the eastern portions of Northern and Central Luzon, as well as some areas of Southern Luzon),” she added.

Areas affected include Cagayan, Isabela, Quirino, Nueva Vizcaya, Aurora, and Quezon, which may experience cloudy skies with scattered rains and isolated thunderstorms. PAGASA warned of possible flash floods or landslides due to moderate to occasionally heavy rainfall.

The northeast monsoon continues to affect the rest of Northern and Central Luzon, bringing cooler temperatures and periods of rain.

“Ang amihan ay patuloy din namang magdudulot ng pag-ulan at malamig na panahon sa natitirang bahagi pa ng Northern at Central Luzon (The northeast monsoon will also continue to bring rainfall and cool weather to the remaining areas of Northern and Central Luzon),” De la Cruz-Galicia said.

Provinces such as Batanes, Apayao, Kalinga, Mountain Province, and Ifugao are forecast to have cloudy skies with rain, with light to moderate rainfall that may become heavy at times, posing flood and landslide risks in mountainous areas.

In Metro Manila, the Ilocos Region, the rest of the Cordillera Administrative Region, and the rest of Central Luzon, the amihan will bring partly cloudy to cloudy skies with isolated light rains, with no significant impacts expected.

In the south, the ITCZ is affecting southern Mindanao, particularly the Zamboanga Peninsula, Davao Region, SOCCSKSARGEN, Basilan, and Tawi-Tawi.

These areas, De la Cruz-Galicia said, may experience cloudy skies with scattered rains and thunderstorms, with PAGASA warning of possible flash floods or landslides due to moderate to heavy rains.

Meanwhile, De la Cruz-Galicia said the easterlies, or warm winds from the Pacific Ocean, are influencing weather conditions over the Bicol Region, Caraga, Northern Samar, Eastern Samar, and Southern Leyte.

Cloudy skies with scattered rains and thunderstorms are expected, with flooding and landslide risks during periods of heavy rainfall, she added.

For the rest of the country, skies will be partly cloudy to cloudy with isolated rainshowers or thunderstorms, which may still trigger localized flooding during severe thunderstorms.

De la Cruz-Galicia urged residents in affected areas to stay vigilant, monitor official weather advisories, and take precautionary measures, especially in flood- and landslide-prone communities, as multiple weather systems continue to affect the country.