MANILA, Philippines -- Tropical Storm "Mina" (international codename: Mitag) could change its course and make landfall in Central or Northern Luzon, instead of the Bicol Region as forecast earlier, the chief state weather forecaster said Thursday.

"The storm hitting Bicol is our official track line, but we have a second scenario. We are looking at the possibility that it would veer towards Central and Northern Luzon, based on forecast models," Philippine Atmospheric Geophysical Astronomical Services Administration (PAGASA) Director Prisco Nilo said.

Nilo said there was a "possibility" that "Mina" could strengthen into a super typhoon since it has two more days to gather strength in open sea before hitting land.

Should the storm hit the Bicol, Nilo said it would make landfall in the northern portion of the region by Saturday morning. But if it changes direction, it could hit Aurora or Isabela province on Sunday morning.

At 4 a.m., "Mina" was spotted 630 kilometers east of Virac town in Catanduanes province. The storm strengthened overnight, packing maximum sustained winds of 115 kilometers per hour and gusts of up to 145 kilometers per hour near the enter, PAGASA said in its 5 a.m. bulletin.

The storm was forecast to be at 300 kilometers east of Virac by Friday morning, 40 kilometers northeast of Virac by Saturday morning, and in the vicinity of Alabat, Quezon by Sunday morning.

Office of Civil Defense Deputy Administrator Anthony Golez said the possible shift could reduce the scale of the evacuation in Albay province in Bicol, which had been ordered by President Gloria Macapagal-Arroyo as a preventive measure.

"[The evacuation] will start at 12 noon in Albay. The figure may go down because of the change in track of the typhoon," Golez said in a text message.

"If it changes track, then [evacuation] will prioritize landslide and

lahar-prone areas," said Golez, who is also the deputy presidential spokesman and spokesman for the National Disaster Coordinating Council (NDCC).

Public Storm Signal number 2 was raised in Catanduanes province, while signal number 1 was raised in the Camarines provinces, Sorsogon, Albay, southern Quezon, and Polilio Island.

Interviewed on local radio, PAGASA weather branch chief Nathaniel Cruz said storm signals could be raised in Metro Manila as the storm nears, and the weather bureau would recommend to the NDCC whether classes should be suspended.

"Mina" will come less than a week after tropical storm "Lando" (international codename: Hagibis) ravaged the Visayas and northern

Mindanao, leaving 10 people dead, 11 wounded, and six missing according to the NDCC.