Batanes province was placed under tropical cyclone warning signal number one as the country's fifth tropical cyclone named ''Ester'' strengthened in Northern Luzon early Friday.

According to the state weather bureau, a low pressure area at the northwest of Batanes that intensified into Tropical Depression ''Ester'' is enhancing the southwest monsoon bringing rains over some provinces in the western section of Luzon.

As of 5 am, the heavy rainfall outlook shows that 100 to 200 mm rain is expected over Ilocos Sur and La Union while 50 to 100 mm of rain is expected in Ilocos Norte, Pangasinan, Abra, Benguet and Zambales.

Around 50 to 100 mm rainfall is also expected in Ilocos Norte, Ilocos Sur, La Union, Pangasinan, Abra, Benguet and Zambales by Saturday while Ilocos Norte and Ilocos Sur will continue to experience the same condition until Sunday.

As of 5 pm, ''Ester'' with maximum sustained winds of 45km near the center and gusts of up to 55 kph was last spotted at 250 km north of Itbayat, Batanes while moving east northeastward at the speed of 15 kph.

"Tropical Depression Ester is forecast to move generally northeastward and exit the Philippine Area of Responsibility (PAR) tonight or tomorrow (June 6) morning over east of China Sea," the Philippines Atmospheric Geophysical Astronomical Services Administration (Pagasa).

"Although Ester may remain as a tropical depression over the waters east of Taiwan, it may eventually reach tropical storm category over the East China Sea," he added. Robina Asido/PHS