Surfers heading to the North Shore over the next couple of days can thank the remnants of former Super Typhoon Choi-wan for the large waves that are expected to reach the Islands.

Choi-wan, which threatened Japan and other parts of Asia a few days ago, is now a large low-pressure system south of the Aleutian Islands. Although thousands of miles from Hawai'i, the system has generated ocean swells that could cause surf of 15 feet later this afternoon or tonight on north-facing shores.

Forecasters believe the big surf could be the first in what may be a busy season of high surf for the Islands.

"The system that created the swell did come from a tropical low originally, so it's not necessarily tied into our typical swell-makers," said John Bravender, National Weather Service forecaster. "But we're in an El Ni—o year and during El Ni—o years we tend to see stronger winter storms going across the North Pacific and a more active surf season during our winters."

Bravender said the surf should begin to rise today and remain at advisory levels through Saturday. Surf heights should begin to fall on Sunday, he said.

The National Weather Service issues high surf advisories when waves are forecast to reach 15 feet on north-facing shores and 8 feet for south- and east-facing shores. High surf warnings are issued when waves on the North Shore hit 25 feet and 15 feet for south-facing shores.