The Philippines prepared Tuesday to evacuate potentially tens of thousands of people as the fifth major storm in three weeks bore down on the archipelago shortly after the onslaught of Typhoon Toraji.
Now a weakened tropical storm, Toraji blew out to sea overnight after causing relatively limited damage and no reported deaths.
But Tropical Storm Usagi is now just two days away from the coast of Luzon, the archipelago nation's largest and most populous island, and gaining strength, the national weather agency said.
"It's looking like it will follow the track of (Yinxing)," civil defence chief Rueli Rapsing of Cagayan province told AFP, referring to a typhoon that struck the northern tip of the country last week.
"We preemptively evacuated 40,000 people that time, so we could be looking at the same scenario and evacuate 40,000 individuals again," he said, adding Cagayan officials will decide on it at a meeting on Wednesday.
Rapsing said the water level of the Cagayan river, the country's largest, was four metres (13 feet) above normal, preventing more than 5,000 people who were previously evacuated from returning home.
He said he also dispatched a search and rescue team to Amulung town after two young men went missing while collecting driftwood from the Cagayan river's swollen waters.
The local government also reported knee-high floods across Santiago, a city of 150,000 people along an upper bank of the Cagayan river.
In all the government said it had evacuated more than 32,000 people from vulnerable areas in the northern Philippines ahead of Toraji's Monday landfall.
The evacuations follow Severe Tropical Storm Trami, Typhoon Yinxing and Super Typhoon Kong-rey, which killed a combined 159 people.
Most of the fatalities happened during Trami, which unleashed torrential rains that triggered deadly flash floods and landslides.
Usagi is now packing 95 kilometres (59 miles) an hour and may start affecting the Philippines late Tuesday, the national weather service said in an updated bulletin.
"This tropical cyclone is forecast to steadily intensify in the next three days and reach typhoon category tomorrow afternoon or evening. (Usagi) will possibly make landfall at peak intensity" on Thursday, it added.
Coastal waters will be rough and "mariners of small seacraft... are advised not to venture out to sea under these conditions".
While the government reported no casualties from Toraji, it said around 15,000 people were still sheltering at mainly government-run evacuation centres.
Utility workers on Tuesday repaired damaged bridges, restored electricity and cleared roads blocked by landslides, fallen trees and power pylons, the civil defence office said.
The full extent of the damage to private homes was not immediately known, but 29 towns and cities were still without power. Ports reopened, meanwhile, and college and university students in nearly 600 towns and cities began returning to class.
"A small number of people were preemptively evacuated but they have since returned home. Classes at the collegiate level have resumed," civil defence official Randy Nicolas of the northern province of Ilocos Norte told AFP.
After Usagi, the weather service said Tropical Storm Man-yi, now near Guam, may also threaten the Philippines early next week.
About 20 big storms and typhoons hit the archipelago nation or its surrounding waters each year, killing scores of people and keeping millions in enduring poverty.
A recent study showed that storms in the Asia-Pacific region are increasingly forming closer to coastlines, intensifying more rapidly and lasting longer over land due to climate change.
