This weekend could see heavy rain and flooding in the northern portion of the Philippines as slow-moving Tropical Storm Koppu nears the island chain.

The storm, also dubbed Lando in the Philippines, is chugging toward the Philippines at about 15 mph. While some wind shear is keeping it somewhat in check, Koppu is headed for an exceptionally warm patch of water that should help the storm become a typhoon with winds equivalent to a Category 3 hurricane.

Koppu Satellite

Satellite view of Koppu as it slowly churns toward the Philippines.


The storm is likely to reach the Philippines’ northernmost island of Luzon by Friday evening or Saturday morning, local time. Koppu’s winds — while they shouldn’t be discounted — aren’t the main issue with the storm, though.

Instead, it’s rain and lots of it. Koppu’s slow pace means the storm could spend two days over the northern portion of Luzon, unleashing an absolute torrent. While Manila will likely be spared the worst impacts, widespread areas on the northern portion of the island could see up to 2 feet of rain through the weekend. That’s as much precipitation as Minnesota sees in a year. Other areas could see even more than that, particularly higher elevation peaks. Some models are calling for up to 4 feet of rain, which could trigger flash floods and mudslides.

Koppu Track

The track of Typhoon Koppu through this weekend.


The Capital Weather Gang’s Angela Fritz notes that not making landfall could be even worse since the storm’s core wouldn’t be weakened by the tall mountains. That would help it unleash more havoc on lower lying areas.

Koppu is the 24th named storm in the western Pacific this year. By one metric — accumulated cyclone energy or ACE — the tropical cyclone season has been much more vigorous in 2015 compared to average in the western Pacific. The eastern Pacific is also having a much more active cyclone season. At one point this summer, four cyclones spanned the Pacific Ocean like pearls of swirling wind and rain.

A big driver for the basin-wide uptick in activity is El Niño. The warmer waters associated with it give tropical cyclones the fuel they need to form and strengthen. Climate change has also raised the ocean’s temperatures, though no specific analysis has been done on its impact on this year’s parade of tropical cyclones.