A tropical wave emerged from Africa on August 19, the northern half of which spawned Hurricane Hanna while the second half continued west. It entered the East Pacific by August 28, interacting with a broad cyclonic gyre spawned by a pre-existing surface trough in the region. As the wave reached the western edge of the gyre, it formed an area of low pressure that further organized into a tropical depression around 12:00 UTC on September 6. It intensified into Tropical Storm Lowell twelve hours later. The cyclone moved along the western periphery of an anticyclone over Mexico, and this feature imparted strong upper-level winds on Lowell that limited its peak strength to 50 mph (85 km/h). Wind shear eventually slackened, but the storm progressed into a drier environment and began to weaken. After falling to tropical depression intensity, Lowell turned east and made landfall near Cabo San Lucas around 09:00 UTC on September 11. It opened up into an elongated surface trough nine hours later.