Tropical Storm ''Jenny'' may intensify into a typhoon Monday or Tuesday as it continues to move closer to extreme northern Luzon.

As of 11 am, ''Jenny'' was last spotted at 1,025 km east of central Luzon with maximum sustained wind of 65 kph near the center and gustiness of up to 80 kph while moving west southwestward at the speed of 35kph.

According to the state weather bureau, ''Jenny'' is forecast to become a severe tropical storm on Sunday and a typhoon on late Monday or on Tuesday.

"'Jenny' is forecast to move generally northwestward until Monday. A west northwestward turn towards Luzon Strait-Southern Taiwan area may take place on Tuesday," it said.

"A landfall or close approach scenario over extreme Northern Luzon or northeastern mainland Cagayan is not ruled out since these scenarios are within the forecast confidence cone," the weather bureau added.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) noted that '' Jenny'' is not directly affecting the country but it may still enhance the southwest monsoon, "resulting in possible occasional rains over the western portions of Southern Luzon and Visayas" on Sunday.

"Due to the proximity of the track forecast to extreme northern Luzon, heavy rainfall over Batanes and Babuyan Islands may be experienced on Tuesday or Wednesday," it added. Robina Asido/DMS