The National Hurricane Center reported Saturday morning that Hurricane Simon had strengthened into a Category 4 storm with maximum sustained winds of 150 mph. The center of the hurricane was located about 115 miles south-southwest of Manzanillo, Mexico, and was moving slowly north.

A hurricane warning remained in effect from Punta San Telmo to El Roblito along Mexico's Pacific coast. Forecasters warned that Simon would approach the coast as a major hurricane late Saturday or early Sunday, bringing dangerous storm surge, destructive winds, and life-threatening rainfall.

Simon produced rainfall totals of 10 to 20 inches across portions of southwestern Mexico, with isolated amounts up to 30 inches possible in parts of Michoacan, Colima, and Jalisco through Sunday. Authorities said the rain would cause flooding and mudslides in steep terrain.

Jalisco state officials suspended classes Friday and Monday in 22 coastal municipalities and began evacuating residents from vulnerable areas. Commercial flights at Manzanillo were canceled for the day.

The storm formed earlier in the week and intensified rapidly over the eastern Pacific. An Air Force reconnaissance aircraft was scheduled to investigate Simon later Saturday to gather updated data on its structure and intensity.

Tropical storm-force winds extended outward up to 125 miles from the center. Hurricane-force winds reached up to 15 miles from the center. Residents in the warning area were urged to complete preparations immediately.

The National Hurricane Center noted that some additional strengthening remained possible Saturday before Simon moved inland.