One to two cyclones likely to enter PH in December; La Niña to bring more rains, floods till mid-2021

At least one or two more tropical cyclones may enter the country in December as more rains are expected until early next year due to a strong La Niña, the state weather bureau said.

In an online Climate Outlook Forum on Friday, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said most models suggest that a strong La Niña will peak from November 2020 to January 2021, bringing above normal rainfall conditions across the country.

Ana Liza Solis, chief of PAGASA's Climate Monitoring and Prediction Section, says La Niña could bring above normal rainfall conditions in the country beginning next month except for some near normal rainfall conditions in Mindanao.

With this, Solis said that at least one to two tropical cyclones are expected to develop in the Philippine area of responsibility (PAR) in December.

The public may also be greeted with more rains for the new year 2021 as above normal rainfall conditions will likely prevail over MIMAROPA, Bicol Region, Visayas, and Mindanao including the eastern part of Luzon by January next year.

The rest of Luzon, meanwhile, is expected to receive below to near normal rainfall conditions during the same period.

Rainfall and tropical cyclones forecast

PAGASA announced in early October the onset of a weak to moderate La Niña citing oceanic and atmospheric indicators such as the cooling of sea surface temperature in the central and equatorial Pacific.

La Niña is a weather pattern usually associated with above normal rainfall conditions and increased tropical cyclone activity that could trigger possible flash floods or rain-induced landslides.

As La Niña continues to strengthen, Solis said that it will likely to continue until the March-April-May 2021 season, while at least one to four tropical cyclone is likely to enter the country from January to May.

"Usually, kapag walang La Niña, slim chance ang pagkakaroon ng bagyo. Ngayon, may posibilidad na pumasok kahit isang bagyo mula January to May dahil sa characteristics ng La Niña," Solis explained.

(Usually, when there is no La Niña, there is a slim chance of having a tropical cyclone. Now, there is a possibility of even one cyclone to enter the country from January to May due to the characteristics of La Niña.)

These are the following rainfall forecast of PAGASA for February to May next year:

• February - generally above normal rainfall conditions in CALABARZON, MIMAROPA, including Metro Manila, Bicol, Visayas, and Mindanao, while the rest of the country will receive below to near normal rainfall conditions.

• March - generally near to above normal rainfall conditions across the country

• April - below to near normal rainfall conditions in Luzon, while near to above normal in the Visayas and Mindanao

• May - generally near to above normal rainfall over most of Luzon and the Visayas, while the rest of the country will experience near normal rainfall conditions

Due to La Niña, Solis warned of an increased likelihood of above normal rainfall conditions that could lead to potential adverse impacts such as heavy rainfall, floods, or landslides over highly vulnerable areas.

This could also negatively impact the agriculture sector which could "extensively damage" growing crops due to flooding, especially in low-lying agricultural lands.

Overflowing of rivers and dam spillage are also expected during La Niña, as well as landslides and coastal erosion caused by strong waves or seaside flooding, according to PAGASA

For human health, La Niña could also lead to prevalence of water-borne diseases in flooded areas or even fatalities due to flash floods, it added

Concerned government agencies, as well as the public, were advised to take precautionary measures to mitigate the potential impacts of La Niña.

Meanwhile, the state weather bureau assured that it will continue to closely monitor the ongoing La Niña and will issue regular updates or advisories regarding the phenomenon.