Typhoon Zeke developed from a tropical disturbance in the Western Pacific monsoon trough southwest of Guam.

Increased convection associated with the disturbance was first monitored by the Joint Typhoon Warning Center (JTWC) at 06:00 UTC on July 6, 1991.

Following evidence that the disturbance had developed a low pressure center, the JTWC issued a Tropical Cyclone Formation Alert early on July 9.

[3] After a steady increase in deep convection near the center of the system, the JTWC declared it a tropical depression at noon on July 9.

[2] Tracking west-northwest at 13 km/h (8.1 mph) under the influence of a subtropical ridge to the north,[2][4] the depression made landfall 50 km (30 mi) south-southwest of Manila.

[5][7][nb 3][nb 4] Reports from ships in the South China Sea indicated a highly asymmetric wind profile, with the radius of 55 km/h (35 mph) winds extending over 290 mi (465 km) southeast of the center, but less than 115 mi (185 km) to the northwest, making its structure akin to a large monsoon depression.

Despite the Navy Global Environmental Model and in turn the JTWC calling for recurvature,[2] Zeke reverted to a largely westward track.

[2] Meanwhile, the JMA estimated that Zeke obtained its peak wind speed of 120 km/h (75 mph) and a minimum barometric pressure of 970 mbar (29 inHg).

[3] Zeke weakened slightly after crossing the island,[2] with the JMA downgrading the system into a severe tropical storm on the morning of July 13.

[4] Offshore Fangchenggang, two people died, seven were missing, and nineteen survived after a Vietnamese cargo vessel sank.

The lowest sea-level pressure of 1,003 mbar (29.6 inHg) was recorded at the Hong Kong Royal Observatory just before noon on July 12.