The kind of rain that overwhelms infrastructure
Each year, the Philippine archipelago submits itself to the rhythms of the Pacific, and once again the sea has sent its messenger: Tropical Depression Mirasol, the thirteenth cyclone of 2025, moved toward the Isabela-Aurora coastline on the evening of September 16, carrying with it the weight of heavy rains and the threat of floods and landslides across Northern Luzon. PAGASA tracked the system from 95 kilometers east of Baler, watching it advance westward at 20 kilometers per hour, its winds sustained at 55 kilometers per hour — enough to remind eighteen provinces that nature does not negotiate. In the longer arc of the season, Mirasol arrives not as an anomaly but as a confirmation: September, as forecast, belongs to the storm.
- Mirasol is closing in fast — positioned just 95 kilometers from the Aurora coast Tuesday night, it is expected to make landfall by Wednesday morning with winds gusting to 70 km/h.
- The rainfall threat is the sharpest danger: 100 to 200 millimeters in 24 hours across Isabela, Quirino, and Aurora — enough to overwhelm rivers, destabilize slopes, and displace communities in vulnerable terrain.
- Eighteen provinces from Batanes to parts of Central Luzon are under Signal No. 1, and mariners have been warned off open water as seas along northern coasts build to 2.5-meter waves.
- The storm's path remains uncertain — a northward shift could spare the coast a direct hit, pushing Mirasol over water toward the Luzon Strait instead of through populated land.
- Even as Mirasol crosses, a new low-pressure area has formed 1,320 kilometers to the east, carrying a medium chance of developing into the next depression within 24 hours — the season is not finished.
Tropical Depression Mirasol bore down on the northern Philippines on Tuesday evening, September 16, with landfall along the Isabela-Aurora coast expected by Wednesday morning. Sitting 95 kilometers east of Baler in Aurora province, the system moved westward at 20 kilometers per hour — a slight slowing from its earlier track — with sustained winds of 55 km/h and gusts reaching 70 km/h.
PAGASA's late-night advisory centered its gravest concern on rainfall. Over the following 24 hours, Isabela, Quirino, and Aurora faced 100 to 200 millimeters of heavy to intense precipitation — volumes that routinely trigger flooding and landslides across the region's mountainous terrain. A second band of moderate to heavy rain would reach Cagayan, Ifugao, Mountain Province, Kalinga, and Apayao, with further rainfall expected across Batanes and Ilocos Norte as the system moved inland and weakened through Thursday.
Wind warnings stretched across an expansive territory. Signal No. 1 was raised for 18 provinces and regions by late Tuesday, from Batanes in the far north through the Cordillera and Ilocos region and into parts of Central Luzon. At sea, waves along the northern coasts were forecast to climb to 2.5 meters, and small vessels were advised to stay in port.
The storm's precise track remained in question. A northward shift could steer Mirasol over coastal waters rather than directly through land, sending it into the Luzon Strait by Wednesday evening and out of the Philippine Area of Responsibility by Thursday. Forecasters noted the depression could even re-intensify into a tropical storm once over open water, and potentially a severe tropical storm beyond Philippine territory by Friday.
Mirasol was the thirteenth cyclone to affect the Philippines in 2025 and the third to enter the forecast area in September alone — a pace consistent with PAGASA's seasonal outlook of two to four storms for the month. Even as the bureau tracked Mirasol, a new low-pressure area had formed 1,320 kilometers to the east, carrying a medium chance of developing into a tropical depression within 24 hours, signaling that the season's work was far from done.
Tropical Depression Mirasol was bearing down on the northern Philippines on Tuesday evening, September 16, with forecasters warning that the system would likely make landfall along the Isabela-Aurora coast by Wednesday morning. As of 10 pm that night, the depression sat 95 kilometers east of Baler in Aurora province, moving westward at 20 kilometers per hour—a slight deceleration from its earlier northwest track. The system maintained maximum sustained winds of 55 kilometers per hour with gusts reaching 70 kilometers per hour, enough to pose serious hazards across a broad swath of the archipelago's northern tier.
The Philippine Atmospheric, Geophysical, and Astronomical Services Administration issued its 11 pm advisory with a stark rainfall forecast. Over the next 24 hours, Isabela, Quirino, and Aurora would face heavy to intense precipitation ranging from 100 to 200 millimeters—the kind of volume that triggers flooding and landslides in vulnerable terrain. A second band of moderate to heavy rain, between 50 and 100 millimeters, would drench Cagayan, Ifugao, Mountain Province, Kalinga, and Apayao. The following day, from Wednesday evening through Thursday evening, the system would continue to deliver 50 to 100 millimeters across Batanes, Cagayan, Apayao, and Ilocos Norte as it moved inland and weakened.
Wind warnings covered an expansive territory. Signal No. 1—indicating strong winds and potential damage—had been raised for 18 provinces and regions by late Tuesday, stretching from Batanes in the far north down through the Cordillera, the Ilocos region, and into parts of Central Luzon. The list included major population centers like Cagayan and Isabela, as well as smaller provinces like Apayao and Kalinga. Mariners faced particular peril: the seaboards of Cagayan, Babuyan Islands, Batanes, Isabela, Aurora, and northern Ilocos Norte would experience up to moderate seas with waves climbing to 2.5 meters. The weather bureau advised small vessels to remain in port or take precautionary measures.
The trajectory remained uncertain. If Mirasol shifted its path more northward in the coming hours, it might skirt the coast rather than make a full landfall, moving instead over the coastal waters of Northern and Central Luzon. Should that occur, the system would re-emerge over the Luzon Strait by Wednesday evening or Thursday morning before exiting the Philippine Area of Responsibility entirely by Thursday afternoon or evening. The depression could either hold its current strength or weaken slightly while crossing land, but forecasters noted it had the potential to intensify back into a tropical storm once it reached the Luzon Strait by Thursday morning, and possibly into a severe tropical storm beyond Philippine territory by Friday, September 19.
Mirasol marked the 13th tropical cyclone to affect the Philippines in 2025 and the third to enter the country's forecast area during September, following Tropical Depression Kiko and Tropical Depression Lannie, both of which had passed through in just a few hours. The weather bureau had anticipated between two and four tropical cyclones for the month, so the arrival of a third system underscored the active nature of the season. Meanwhile, a separate low-pressure area that had crossed Southern Luzon over the weekend had dissipated by Tuesday evening, but a new one had formed far to the east—1,320 kilometers from southeastern Luzon—with a medium chance of developing into a tropical depression within 24 hours. The forecast remained fluid, with updates expected as both systems evolved.
Citas Notables
Floods and landslides are possible— PAGASA rainfall outlook
Small vessels advised to take precautionary measures or avoid sailing, as waves can reach up to 2.5 meters high— PAGASA maritime advisory
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter whether Mirasol makes landfall versus just skirting the coast?
The difference is in where the heaviest rain falls. A direct landfall means the core of the system moves inland, dumping that 100-to-200-millimeter rainfall directly over populated areas and steep terrain. If it stays offshore, the rain is still significant but more dispersed, and the system weakens faster over water.
You mentioned it could intensify again over the Luzon Strait. How does that work—it weakens over land, then gets stronger?
Tropical systems feed on warm ocean water. Over land, they lose that energy source and fall apart. But the Luzon Strait is warm water. If Mirasol emerges back over it, it has fuel again to reorganize and strengthen before it leaves the Philippine area entirely.
What does Signal No. 1 actually mean for people living in those 18 provinces?
It means strong winds are coming—the kind that can topple trees, damage roofs, snap power lines. It's not the highest alert, but it's serious enough that people should secure loose objects, stay indoors during the worst of it, and be ready for extended power outages.
The rainfall numbers—100 to 200 millimeters in 24 hours—how does that compare to normal?
That's roughly four to eight inches in a single day. In a region with steep slopes and poor drainage, that volume of water in that timeframe is enough to trigger flash floods and mudslides. It's the kind of rain that overwhelms infrastructure.
Is there a sense of how many people might be affected?
The source doesn't specify displacement numbers, but 18 provinces under warning means millions of people are in the path. The real impact depends on where exactly it lands and how the rain distributes—some areas will see the worst of it, others less so.
What happens after it leaves Philippine territory?
It becomes someone else's problem. It may intensify into a severe tropical storm, but that's outside the Philippines' responsibility to track and warn about. The focus shifts to whatever comes next—and there's already another low-pressure system forming out in the Pacific.