Forecast summary from PAGASA  

MANILA — Three tropical cyclones could barrel through the Philippine area of responsibility this week, the state weather bureau said Monday. 

Typhoon Nika struck the northern Philippines earlier in the day, with thousands of villages ordered to evacuate and ports shut down. 

The typhoon will emerge over the West Philippine Sea on Monday afternoon or evening and will be out of PAR on Tuesday morning.

Thousands flee as fourth typhoon in a month hits Philippines

But before Nika’s exit, a tropical depression could enter the Philippine area of responsibility on Tuesday and would be named Ofel. 

It will continuously intensify while crossing the Philippine Sea. It may reach typhoon strength before making landfall over northern or central Luzon late Thursday or early Friday.

A third cyclone named Man-yi was spotted east of Guam on Monday. It may enter the PAR before the weekend and will be given the local name Pepito.

Pepito may head towards Bicol or Eastern Visayas, PAGASA said. 

Experts explained that the occurrence of storms and typhoons at very short intervals was not new and had been monitored as early as the 1950s.

Ana Liza Solis, PAGASA’s Chief of Climatology Monitoring and Prediction Section, explained that the country was in a La Niña-like condition where sea surface temperatures in the Eastern Pacific Ocean are much cooler than warmer temperatures in the western section. These warmer sea surface temperatures make it favorable for water evaporation and cloud formation, which later result in tropical depressions and storms or even typhoons, she said.

It remains unclear whether the two new weather systems will ultimately make landfall. However, as long as the northeast monsoon winds remain weak or absent, the chances for them to enter and pass through Northern Luzon remains likely.

“Kapag pumapasok kasi yung hangin na dulot ng amihan posibleng ito ay iniiwasan ng bagyo. Ibig sabihin, may possibility po na yung track ng bagyo ay magbago kapag papasok na ang northeast monsoon o yung amihan,” she said.

(Once the northeast monsoon winds enter, typhoons tend to avoid this which makes it possible for the track of future typhoons to change.)

Should this happen, typhoons tend to cross to lower sections of the country particularly Visayas and Mindanao.

PAGASA has not declared the start of the “amihan” or northeast monsoon season yet but says it may “just be around the corner.”

NIKA’S ONSLAUGHT 

On Monday, rescuers said around 7,000 people were moved from coastal areas as well as flood-prone and landslide-prone areas in Aurora and Isabela, the first two provinces to be struck before Nika plowed inland to the mountainous interior of the main island of Luzon.

"We're getting hit with strong winds and heavy rain. Some trees are being toppled and power has been cut since yesterday," Merwina Pableo, civil defense chief of Dinalungan town near Dilasag, told AFP.

"We cannot go out yet to make a damage assessment."

Signal 4 up as Nika bears down on northern Luzon

In all, the government ordered 2,500 villages to be evacuated on Sunday, though the national disaster office does not have the total number of evacuees as of Monday.

In the landfall area of Dilasag, Aurora, school teacher Glenn Balanag, 31, filmed the onslaught of the howling 130 kilometers an hour winds, which violently shook coconut trees around his rural home.

"Big trees are falling and we heard the roofs of some houses were damaged. The rain is continuing and a river nearby is rising," he told AFP.

Thousands flee as fourth typhoon in a month hits Philippines

The national weather agency warned of severe winds and "intense to torrential" rainfall exceeding 200 millimeters (eight inches) across the north of the country, along with a "moderate to high risk of a storm surge" -- giant waves up to three meters high on the north coast.

Nearly 700 passengers were stranded at ports, according to a coast guard tally on Monday, with the weather service warning that "sea travel is risky for all types or tonnage of vessels".

"All mariners must remain in port or, if underway, seek shelter or safe harbor as soon as possible until winds and waves subside," it added.

Aurora and Isabela officials said the main impact appeared to be downed trees and power pylons that blocked major roads.

"I don't want to send people out yet to investigate. I do not want them to be caught out by powerful gusts," said Constante Foronda, Isabela's disaster response chief.

GREATER CAUTION NEEDED 

Chris Perez, PAGASA senior weather specialist, explained the severity of rainfall could have varying effects depending on where it happens. This means that intense to torrential rainfall will not always have the same impact in every locality.

“Halimbawa may bagyong nagpaulan ng 200 millimeters sa Metro Manila which is highly urbanized, babaha talaga. Yung 200 millimeters of rain na yan, kung babagsak sa rural areas hindi magiging ganiyan ka-immedate ang epekto,” he said. 

(For instance 200 millimeters of rain pouring in Metro Manila, a highly urbanized area, will definitely result in flooding. But the same amount of rain, if it happens in a rural area, will not have the same impact.)

The series of typhoons that has battered the country, particularly Luzon, the past couple of months calls for extreme caution to be exercised especially for those living in landslide-prone areas. 

PAGASA Deputy Administrator for Research Dr. Marcelino Villafuerte explained that regularly occurring rain puts certain communities at risk as land tends to become highly saturated by water thereby increasing the risk for landslides. 

The weather systems outside PAR may just make it worse. 

“Given itong projections na yung dalawang paparating na bagyo pa ay roughly doon din posibleng dumaan, then definitely ang impact nito ay mag mu-multiply pa given na saturated ang lupa,” he said. 

“Given that the projections of the two new typhoons show roughly the same track as of previous typhoons, it will definitely multiply potential impacts,” Villafuerte said. 

Experts call on the public to remain alert by keeping updated with latest rain, flood and weather advisories, as well as heed the advice of local governments to keep themselves safe amid extreme weather.

PNP ON HEIGHTENED ALERT 

All police regional offices have been placed on heightened alert for Typhoon Nika and the two other succeeding cyclone, a police official said Monday.

Philippine National Police spokesperson BGen. Jean Fajardo said police were helping with the pre-emptive evacuation, particularly in northern Luzon.

The Reactionary Standby Support Force (RSSF) has also been activated to bolster the police force and possibly lead incident management and disaster response.

“Sa ngayon po, ang talagang focus natin is Region 2, northern Luzon dahil magkakasunod po, from typhoon Kristine, typhoon Leon, and now typhoon Nika. So, andyan po ang concentration natin,” Fajardo said in a media briefing.

Interior Secretary Jonvic Remulla earlier said the soil in cyclone-hit areas was saturated and the risk of landslides was high.

“Meron na rin pong direktibang ibinaba rin po ang DILG, ang ating secretary, for all PROs to coordinate with their respective LDRRMC and LGU to prepare po dito po sa Nika, and even po Ofel, and even Pepito po,” Fajardo said.

Nika came on the heels of three cyclones in less than a month that killed 159 people.

On Thursday, Typhoon Marce slammed into the country's north coast, damaging houses and buildings.

A 12-year-old girl was crushed to death in one incident.

Before that, Severe Tropical Storm Kristine and Super Typhoon Leon together left 158 people dead, the national disaster agency said, with most of that tally attributed to Trami.

About 20 big storms and typhoons hit the archipelago nation or its surrounding waters each year.

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.

Supercharged storms: how climate change amplifies cyclones

— With reports from Ariel Rojas, Raphael Bosano, Michael Delizo, ABS-CBN News; Agence France-Presse