''Nando'' intensified into a tropical storm Friday as it was located 905 kilometers east of Central Luzon, with winds of 85 kilometers and gusts of up to 105 kilometers per hour.

In its 5 pm advisory, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) said wind signal number one will be raised over Northern Luzon Saturday morning. ''Onset of heavy rains due to the southwest monsoon is possible by Sunday, '' said Pagasa.

It could reach super typhoon category as Pagasa said ''the highest wind signal that may be hoisted throughout its passage is Wind Signal Number 5.''

The southwest monsoon and the trough of ''Nando'' will ''bring strong to gale-force gusts over Bicol. Western Visayas and Caraga on Saturday. On Sunday, these gusts will reach Calabarzon, Bicol Region, Visayas, Northern Mindanao and Caraga. DMS