Jenny has intensified into a typhoon over the Philippine Sea Monday and continues to threaten parts of Northern Luzon, weather bureau PAGASA said.

As of 4 a.m., the center of the eye of Typhoon Jenny was estimated based on all available data at 655 km East of Aparri, Cagayan or 665 km East of Calayan, Cagayan.

Packing 120 kph winds and gusts of up to 150 kph, Jenny is presently moving northwestward at 10 kilometers per hour.

PAGASA weather forecaster Obet Badrina noted there is little chance that Jenny will make landfall in any part of the country.

He added that a gale warning is in effect for the coastal waters of Batanes and Babuyan Islands. Jenny will also bring moderate to rough seas (2.0 to 4.0 m) over the coastal waters of mainland Cagayan.

"Mariners of motor bancas and similarly-sized vessels are advised to take precautionary measures while venturing out to sea and, if possible, avoid navigating in these conditions, especially if inexperienced or operating ill-equipped vessels," the weather bureau said.

Tropical Cyclone Wind Signal No. 1 is hoisted over the following areas"

• Batanes,
• Babuyan Islands,
• eastern portion of mainland Cagayan (Santa Ana, Gonzaga, Buguey, Santa Teresita, Lal-Lo, Baggao, Gattaran, Peñablanca),
• eastern portion of Isabela (Maconacon, Divilacan, Palanan)