Turning to the north, Zeb brushed the east coast of Taiwan at a reduced intensity, and after accelerating to the northeast it moved through Japan.

First affecting the Philippines, Zeb dropped torrential rainfall in Luzon, reaching 1,116 millimetres (43.9 inches) in one day in La Trinidad, estimated as a one-in-1,147-year event.

The monsoon trough spawned a tropical disturbance over the western Pacific Ocean to the east of Guam around October 7.

The system moved steadily westward, organizing enough for the American-based Joint Typhoon Warning Center (JTWC) to issue a Tropical Cyclone Formation Alert early on October 9.

After the disturbance passed south of Guam, the JTWC began issuing advisories on Tropical Depression 18W late on October 9,[1] and the Japan Meteorological Agency (JMA) followed suit the next day.

[2] While passing north of Yap in the Caroline Islands, the depression intensified into a tropical storm according to the JTWC, which gave it the name Zeb.

[1] Early on October 11, the storm entered the area of responsibility of PAGASA – the Philippine-based weather agency – which gave it the local name Iliang.

During this time, it caused increased wind shear over the smaller Tropical Storm Alex to the east-northeast, ultimately absorbing it.

Twelve hours later, the agency estimated that the typhoon strengthened further to a peak of 285 km/h (180 mph), making it the strongest storm of the season.

[6] Early on October 14, Zeb made landfall on eastern Luzon just south of Palanan Bay, or east of Ilagan, near peak intensity.

[1][4] It emerged into the Luzon Strait between the eponymous island and Taiwan with a much larger eyewall,[6] and failed to re-intensify over open waters.

[1] Favorable upper-level conditions allowed the storm to briefly re-intensify after passing Taiwan, although this was short-lived, and it weakened while accelerating toward Japan.

It continued northeastward through the country, striking Kōchi Prefecture on Shikoku and later crossing central Honshu as a tropical storm.

[1] At 00:00 UTC on October 18, the JMA declared Zeb extratropical, and shortly after the storm moved over northern Hokkaido and into the Sea of Okhotsk.

[8] After two damaging storms in September, the government began making widespread preparations on October 13, organizing efforts through its National Disaster Coordinating Council.

[8] The Hong Kong Observatory issued a stand-by warning signal #1 due to the storm's proximity to the South China Sea.

[14] Before Zeb brushed the east coast of Taiwan, a typhoon warning was issued, causing schools, government buildings, and financial markets to close.

[4] The Binga and Ambuclao dams in Benguet were unable to support the rains from the storm, forcing them to be opened and flood three towns in neighboring Pangasinan.

[24] River flooding caused heavy damage to crops,[22] estimated at ₱1.76 billion (1998 Philippine pesos, $41.3 million U.S. dollars);[20] the storm destroyed 181,630 t (400,430,000 lb) of rice in Ilocos Region and Cagayan Valley.

[25] The storm also marred the local infrastructure; areas in northeastern Luzon were isolated when landslides blocked a highway,[22] and several other roads and bridges were impassible.

[27] The interaction between Zeb and the monsoon brought gusty winds to Hong Kong, reaching 88 km/h (55 mph) on Cheung Chau.

[25] The typhoon dropped torrential rainfall in the northern and eastern portions of the island, with peak hourly rates of 42.1 mm (1.66 in).

[14] While moving through Japan, Zeb produced peak sustained winds of 130 km/h (81 mph) in Kōchi Prefecture within Shikoku.

[45] Lastly, Zeb affected the northern island of Hokkaido, causing one landslide, damaging 152 buildings, and knocking 152,000 apples to the ground.

[24] The military was activated to help organize relief efforts,[15] using rubber boats and trucks to reach the hardest hit areas as floodwaters decreased.

[1] After both storms, the Philippine National Electrification Administration provided ₱1.78 million to the Batanes Electric Cooperative to restore damaged power lines.