The storm is not yet over in Northern Luzon, with the government’s weather office placing Ilocos Norte under Storm Signal No. 3 Monday afternoon.

Weather forecasters warned that stormy weather will continue to prevail in the Ilocos region for the next three days after typhoon “Pepeng,” now a tropical storm, intensified Monday afternoon while staying in a “stationary state” in the South China Sea near Laoag City since Sunday afternoon.

The Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) explained that the entrance of Typhoon “Quedan” in the country Monday noon had pulled back Tropical Storm “Pepeng” in Northern Luzon in what weather forecasters called “the Fujiwara effect.”

Instead of heading towards Hong Kong, “Pepeng” stayed and threatens to stay in the northeastern part of South China Sea around 220 kilometers north-northwest of Laoag City until Thursday, exposing Ilocos provinces to more heavy rains and gusty winds that could generate storm surges.

“This is what we call the Fujiwara effect, (where) there is a fulcrum or axis that when one tropical cyclone moves (one) way, the other one goes the opposite way. We are experiencing a dumbbell effect,” PAGASA Director Nathaniel Cruz told reporters in a press briefing yesterday.

The Fujiwara effect is a type of interaction between two eyes of tropical cyclones, causing them to appear to "orbit" each other. When the cyclones approach each other, their centers will begin orbiting cyclonically about a point between the two systems.

Cruz said Typhoon “Quedan” was spotted in the Philippine Sea at about 1,130 kilometers east southeast of Basco, Batanes, packing maximum sustained winds of 205 kph near the center and gustiness of 250 kph while moving northeast towards Okinawa, Japan as of 4 p.m. Monday.

He added that Storm Signal No. 3, which was hoisted over Ilocos Norte yesterday afternoon, might be maintained over the province in the next three days as “Pepeng” interacts with “Quedan” and could cause heavy damage to agriculture, uproot large trees, destroy houses, and topple down power lines.

PAGASA administrator Prisco Nilo said that “Quedan” has caused “Pepeng” to recurve back to Northern Luzon, threatening to directly hit Ilocos Norte and the Batanes group of islands by Thursday or after three days.

Nilo added that Tropical Storm “Pepeng” could intensify further into a tropical cyclone for the second time during its prolonged stay in the South China Sea in the next three days before Typhoon “Quedan” drags the disturbance to hit Ilocos Norte and Batanes towards Taiwan on Thursday.

But he clarified that “Quedan,” which has been expected to be out of the Philippine area of responsibility this afternoon to start moving towards Japan, could drag “Pepeng” eastward towards Taiwan as far as Batanes, where the storm could stay for a while starting Thursday.

Nilo noted that the storm is already making a loop towards northeast, but clarified that the ridge of High Pressure Area (HPA) near the vicinity of Hong Kong could push “Pepeng” towards the Vietnam and dissipate over the South China Sea.

Storm Signal No. 2 was raised over Ilocos Sur, Abra, Apayao, Northern Cagayan including Calayan and Babuyan groups of islands as well as Batanes that could have heavy rains while Storm Signal No. 1 was hoisted over La Union, Benguet, Mountain Province, Ifugao, Kalinga, and rest of Cagayan.

Nilo assured that flood stricken Metro Manila will experience improved weather conditions, experiencing only partly cloudy with light scattered rain showers and thunderstorms.