"Julian" (international name, Maysak) further intensified from a tropical depression to a tropical storm on Friday afternoon, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) said.
PAGASA weather specialist Ariel Rojas said that the tropical storm will continue to intensify as it will remain over the Philippine sea throughout its forecast period.
According to Rojas, it is expected to reach severe tropical storm category by Saturday afternoon and typhoon category by Sunday morning before exiting the Philippine area of responsibility (PAR) on Monday.
However, Rojas said that the raising of tropical cyclone wind signal due to the tropical storm is not expected and Julian is less likely to directly affect the weather over the country as it is far from the landmass.
In PAGASA's 5 p.m. weather bulletin issued Friday, Julian was located at 880 kilometers east of Tuguegarao City, Cagayan while moving west northwest at 15 kilometers per hour (kph).
It packs maximum sustained winds of 65 kph near the center and gustiness of up to 80 kph.
Based on its forecast track, Julian is expected to be at 875 kilometers east of Aparri, Cagayan on Saturday afternoon and at 835 kilometers east of Basco, Batanes on Sunday afternoon.
While the tropical storm is not expected to directly affect the country, its trough or extension, as well as the southwest monsoon or "habagat" will bring rainshowers this weekend.
In Metro Manila, CALABARZON, Bicol Region, Nueva Ecija, Bulacan and Aurora, cloudy skies with scattered rainshowers and thunderstorms will prevail due to the trough of Julian and habagayt.
Partly cloudy to cloudy skies with isolated rainshowers is expected over the rest of the country caused by the southwest monsoon and localized thunderstorms.
A gale warning was also raised by the state weather bureau on the northern and western seaboards of Northern Luzon due to the southwest monsoon.
With this, moderate to strong winds are expected to affect the coasts of Batanes, Babuyan, and Ilocos Norte.
PAGASA warned that sea travel is risky, especially for small sea crafts, over seaboards where a gale warning was raised due to moderate to rough force winds and wave height of up to 3.4 meters.