At least one to two tropical storms may form within the Philippine Area of Responsibility this June, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said on Sunday.

In a phone interview, PAGASA Weather Specialist Rhea Torres said most storms forming in June typically do not make landfall.

“Because of the southwest monsoon, there is a tendency to recurve. If there is a landfall scenario, there’s a chance that it may occur over the eastern section of Southern Luzon,” Torres explained.

Last Friday, PAGASA officially declared the onset of the southwest monsoon, citing persistent low-level southwesterly winds over the western section of Luzon and a frontal system over Extreme Northern Luzon.

The weather bureau also said the official start of the rainy season could be declared within the next two weeks.

In Metro Manila and nearby provinces, sudden heavy downpours on Friday and Saturday afternoons caused flooding in some areas.

Torres noted that thunderstorms may continue over the next two to three days.

“In Northern Luzon, cloudy conditions are expected to continue for the next two days, while in Central Luzon, specifically Zambales and Bataan, the rains may persist but a gradual improvement of weather is possible over the next few days.”

The southwest monsoon remains the prevailing weather system, with localized thunderstorms forecast to affect the rest of the country.

According to PAGASA’s 24-hour rainfall forecast, 50 to 100 millimeters of rain are expected in Batanes, Babuyan Islands, Ilocos Norte, Ilocos Sur, Abra, La Union, Pangasinan, Zambales, and Bataan due to the southwest monsoon.

As of Sunday, no low-pressure area has been detected within the Philippine Area of Responsibility.