The La Niña may continue to bring above average rainfall across most of the country until early 2021, increasing the risk of heavy rainfall, floods, and landslides across the country, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).
PAGASA noted that most climate models still suggest that a strong La Niña occurrence will reach its peak within the last quarter of 2020 and continue through March-April-May 2021.
A La Niña is classified as a strong event once it reaches sea surface temperature of at least 1.5 degrees Celsius, which is colder than average.
The last time there was a strong La Niña was in 2010-2011, followed by a moderate event in 2011-2012, PAGASA said.
It explained that with a strong La Niña, the likelihood of above normal rainfall condition increases across most areas of the country during the last quarter of this year until the early months of the following year, which “could lead to potential adverse impacts, such as heavy rainfall, floods, and landslides over highly vulnerable areas.”
La Niña is known to increase the potential of having extreme rainfall events caused by rain-bearing weather systems.
The weather systems that will likely affect the country in December are the northeast monsoon or amihan, localized thunderstorms, tail-end of frontal system, low pressure areas, intertropical convergence zone, enhanced easterlies, and the occurrence of one or two tropical cyclones that may enter or develop within the Philippine area of responsibility.
Based on the PAGASA’s rainfall forecast for December, most parts of the country will generally experience above normal rainfall conditions, while some parts of Mindanao will likely receive near normal rainfall.
By January 2021, PAGASA said rainfall will be above average in Oriental Mindoro, Occidental Mindoro, Marinduque, Romblon, Palawan, Albay, Catanduanes, Camarines Norte, Camarines Sur, Sorsogon, Masbate, Visayas, Mindanao, including eastern Luzon.
Meanwhile, the rest of Luzon will likely to receive below to near average rainfall.
By February 2021, PAGASA said generally above average rainfall will likely be felt in Cavite, Laguna, Batangas, Rizal, Quezon, Metro Manila, Albay, Catanduanes, Camarines Norte, Camarines Sur, Sorsogon, Masbate, Visayas, and Mindanao, while the rest of the country will receive below to near average rainfall.
PAGASA also noted that by March 2021, rainfall conditions will be generally near to above normal across the country, and by April 2021, below to near normal rainfall may affect Luzon and near to above normal rainfall in Visayas and Mindanao.