Tropical Storm Vamei (international designation: 0126, JTWC designation: 32W, sometimes called Typhoon Vamei; formerly had the alternate name Tropical Storm 05B) was a Pacific tropical cyclone that formed closer to the equator than any other tropical cyclone worldwide. The last storm of the 2001 Pacific typhoon season, Vamei developed on December 26 at 1.4° N in the South China Sea. It strengthened quickly and made landfall along extreme southeastern Malaysia. Vamei rapidly dissipated over Sumatra on December 28, and the remnants eventually re-organized in the North Indian Ocean.

Though officially designated as a tropical storm, the intensity of Vamei is disputed; some agencies classify it as a typhoon, based on sustained winds of 140 km/h (85 mph) and the appearance of an eye. The storm brought flooding and landslides to eastern Malaysia, causing $3.6 million in damage (2001 USD, $4.73 million 2012 USD) and five deaths.

A tropical cyclone is a storm system characterized by a low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor contained in the moist air. They are fueled by a different heat mechanism than other cyclonic windstorms such as nor'easters, European windstorms, and polar lows. The characteristic that separates tropical cyclones from other cyclonic systems is that at any height in the atmosphere, the center of a tropical cyclone will be warmer than its surroundings; a phenomenon called "warm core" storm systems.

The term "tropical" refers both to the geographical origin of these systems, which usually form in tropical regions of the globe, and to their formation in maritime tropical air masses. The term "cyclone" refers to such storms' cyclonic nature, with counterclockwise wind flow in the Northern Hemisphere and clockwise wind flow in the Southern Hemisphere. The opposite direction of the wind flow is a result of the Coriolis force. Depending on its location and strength, a tropical cyclone is referred to by names such as hurricane (/ˈhʌrɨkeɪn/, /ˈhʌrɨkən/), typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone.