By Ellalyn De Vera-Ruiz
Published Jul 18, 2025 03:28 pm
While the southwest monsoon, or “habagat,” remains the main source of rain from July to September, scientists say the “indirect” effect of distant tropical cyclones accounts for about a third of total rainfall during this season.
Researchers from Ateneo de Manila University (AdMU); Manila Observatory; Philippine Atmospheric, Geophysical and Astronomical Services Administration; and Japanese partner institutions analyzed 62 years of weather data and found that tropical cyclones hundreds of kilometers away can strengthen the habagat, resulting in heavy rains, even without making landfall.
On average, 33.1 percent of rainfall during the habagat season is attributed to this “indirect” effect, more than twice the 15.4 percent caused by tropical cyclones that directly hit the country.
The remaining 51.5 percent comes from the monsoon itself, without tropical cyclone influence.
Cyclone origin matters
The study pointed out that the cyclone’s genesis point, or location where a tropical cyclone forms, also affects its potential to enhance rainfall.
Tropical cyclones that form farther from the Philippines tend to move northeast of Luzon, where they more effectively intensify monsoon winds.
In contrast, cyclones that form closer often take a shorter westward track and have a weaker effect.
“During the peak months of the southwest monsoon season, from July to September, the prevailing winds over the Philippines are from the southwest. In itself, these moisture-laden southwesterly winds can still produce isolated rainfall events over land,” explained Dr. Lyndon Mark Olaguera, assistant professor at AdMU’s Department of Physics and climate scientist at the Manila Observatory.
“When a tropical cyclone passes to the northeast of the Philippines, these southwesterly winds intensify since the tropical cyclone can pull these winds as a result of its counterclockwise circulation. Stronger southwesterly winds usually mean more intense rainfall over land,” he said.
Most at risk
The researchers cited Typhoon Gaemi (locally known as Super Typhoon Carina) in July 2024 as an example of a tropical cyclone that stayed well away from the Philippine landmass but significantly enhanced the habagat.
During that event, Quezon City received nearly a month’s worth of rain within 24 hours, resulting in floods that killed 48 people and caused over P8 billion in damages.
Olaguera said the western coast of Luzon is particularly vulnerable to indirect cyclone rains.
“This is because winds from the enhanced southwest monsoon are from the southwest; therefore, the western coast is the region that gets affected the most,” he explained.
“Additionally, the high mountains near the western coast of Luzon, like the Cordillera Mountains and the Zambales mountain range, force these moist, southwesterly winds upwards as they flow over the mountains. When these winds are forced upwards, they cool and condense, thus producing rainfall,” he said.
Forecasting challenges
While direct landfalling cyclones remain deadlier, Olaguera emphasized the need to pay closer attention to the impacts of cyclone-enhanced monsoon events.
“More importance should be given to tropical cyclones that enhance the southwest monsoon since the rainfall experienced during these indirect events is comparable to the rainfall experienced during direct tropical cyclone events,” he said.
He noted that indirect effects are harder to predict, as not all distant cyclones enhance the monsoon enough to cause extreme rainfall.
“More research should be done in order to increase the forecast accuracy of these enhanced southwest monsoon events,” he added.
Recommendations
To improve early warning systems, Olaguera recommended expanding the Philippine Area of Responsibility (PAR) westward and northward to include more tropical cyclones that can affect the country’s weather even from afar.
“Extending the northern border to 30°N will include regions where tropical cyclones are still able to produce rainfall over the Philippines. An example is Typhoon Haikui (2012), since it produced extreme rainfall over the Philippines despite being around the latitudes of 26-28°N,” he said.
He also cited Typhoon Danas (2025), which briefly exited the PAR but still caused rainfall over Luzon while located outside the current monitoring zone.
He also recommended the monitoring of moisture flows originating from as far as west, such as the Arabian Sea or Bay of Bengal, which could help in the forecasting of enhanced southwest monsoon events.
Midyear reset: Conquer the rainy day blues with this 10-minute cardio fix
Now that the rainy season has arrived, it’s common to feel a bit off—moods can shift, energy may dip, and staying consistent with healthy habits becomes more challenging. After making it through the first half of the year, you might be feeling the urge to hit reset—to boost your motivation, take better care of your well-being and finish the year feeling strong, grounded, and more like yourself.
By Mitch Felipe Mendoza
I have been writing columns for several papers from all over the world since the early 1980's. Since 1999, while residing in the Philippines for good, I experienced many ups and downs. Sometimes, while writing, I am indeed not in a good mood. I rewrote and rewrote... .
A genuine smile involves the muscles around your eyes (the "Duchenne smile"), conveying positive emotions and strengthening social bonds according to Verywell Mind. Smiling also triggers the release of endorphins, which can improve mood and reduce stress.
Smiling is a powerful expression that can have both physical and social benefits. Here's why:
Positive emotions: Smiling is often a result of experiencing happiness, and it can also be a way to express positive emotions to others according to Verywell Mind.
Smiling can signal friendliness and approachability, making it easier to connect with others.
Smiling, even a forced one, can trigger the release of endorphins, which have mood-enhancing effects.
Smiling can lower levels of stress hormones like cortisol and adrenaline, promoting relaxation.
Smiling is linked to lower blood pressure and improved overall well-being.
Anyway, I will try my best. It's actually a sweet day today, so sunny, so calm, so bright, it's like the bridal of earth and heaven. The grandeur of God flames out like shining from shook foil. I feel like the waves make towards the pebbled shore.
I observed again a multi national couple somewhere in my neighborhood fighting each other. Gosh. Stupid people have an uncanny way of hitting the right nail on the head with the wrong hammer!
Maybe, you are also angry right now, while reading this. You are angry, even for others it's a beautiful day. Are you angry? It's okay. We are all battling against one of the most powerful emotions known to man - anger! Anger. A day rarely goes by without us feeling angry. Or, maybe seldom a day goes by without feeling anger... .
Anger is the main part of our daily life. That's why it's really important to talk about this phenomenon. What is anger, what does it do and how does it affect our lives? Where does it come from and how can we learn to handle it in a constructive instead of destructive way? Only, if the roots of our anger are exposed and explained, can we defuse its explosive and dangerous potentials.
As I said earlier, anger is one of the most basic emotions. Everyone can get angry. You and me? Now, later, tomorrow...! It's a feeling of being against something or someone.
Anger is a hostile emotion that sets people against one another, or even themselves. By its nature, anger involves opposition, hostility, hatred and dislike. It happened between Filipinos, and between Filipinos and foreigners as well, living here in the Philippines. It even happened at the political level right nowadays.
Anger, however, is simpler to define than to identity. Emotions of antagonism can take a wide variety of faces. Expressions of anger range from the overt, in-your-face brand of open hospitality to the cold indifference of a silent individual. At times, anger can be felt like an inner fire... .
Millions of defense, not a damned penny for tribute. Anger between people: the one side remains cold as ice while the opposite plays meek as a lamb. Sige, burn the midnight oil! And what was the result at the end? A shadow of doubt remains after each fight getting its origin out of anger.
The silent withdrawal and lack of understanding and innumerable shortcomings of one or both partners are often an indication that one is angrily punishing the other for not doing things his or her way.
We are all selfish! Yes, me too! That's why we see the cause of anger as something outside of ourselves. Life is unfair! Life is hard!
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The Philippine Atmospheric, Geophysical and Astronomical Services Administration said on Thursday, July 17, that higher wind signals are expected over parts of Luzon as tropical depression “Crising” nears tropical storm strength. It is forecast to reach tropical storm status early Friday morning, July 18, and may intensify further into a severe tropical storm by Saturday morning or afternoon, July 19. Read more | ||
The weather bureau also issued a storm surge warning on coastal areas of Northern Luzon including Cagayan, Ilocos Norte, and Isabela within the next 48 hours. Read more | ||
Meanwhile, classes were suspended in various regions including Western Visayas, Eastern Visayas, and Negros Occidental due to Tropical Depression “Crising.” |
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This image is AI-generated for visual storytelling purposes. The events and locations mentioned are real, based on official reports from geological and seismic monitoring agencies.
