Typhoon ''Betty'' is moving slowly northward as it maintained its strength Tuesday afternoon, the Philippine Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) said.

Weather Specialist Aldczar Aurelio said"Betty" was located at 315 km east of Basco, Batanes with maximum sustained winds of 150 kilometers per hour near the center and gusts of up to 185 kilometers per hour.

''Betty'' is forecast to generally move slowly northward Tuesday until Wednesday over the waters east of Batanes.

''Afterwards, the typhoon will gradually accelerate north northeastward on Thursday and northeastward on Friday, bringing its center over the waters southeast of the Ryukyu Islands,'' said Pagasa.

Batanes remained under Tropical Cyclone Wind Signal Number Two, said Pagasa.

The northern and eastern portions of Isabela (Santo Tomas, Santa Maria, Quezon, San Mariano, Dinapigue, Delfin Albano, San Pablo, Ilagan City, Benito Soliven, Tumauini, Cabagan, Palanan, Quirino, Divilacan, Gamu, Maconacon, Naguilian, Mallig), Apayao, the eastern portion of Ilocos Norte (Piddig, Bangui, Vintar, Marcos, Pagudpud, Banna, Adams, Carasi, Dingras, Solsona, Dumalneg, Nueva Era), the northern portion of Kalinga (City of Tabuk, Balbalan, Pinukpuk, Rizal), the northeastern portion of Abra (Tineg, Lacub, Malibcong) and Cagayan including Babuyan Islands are under Tropical Cyclone Wind Signal Number One.

Rains of 50-100 millimeter are forecast Tuesday to Wednesday afternoon at the southern portions of Ilocos Sur and the northern portion of La Union, Pagasa said. Eric Acidre/DMS