As of 5 a.m. EDT., Wilma had maximum sustained winds of 155 mph -- just 2 mph short of a Category 5.

Even at Category 4, Willa is "extremely dangeorus," forecasters warned, adding that it was likely to strengthen slightly into a Category 5 Monday morning.

The NHC said it could make landfall along Mexico's southwestern coast Tuesday night or Wednesday morning and bring with it a life-threatening storm surge -- especially near and to the south of where the center of Willa makes landfall. Near the coast, the surge will be accompanied by large and destructive waves. Willa is also forecast to bring high winds and heavy rainfall.

"While some weakening is forecast by tonight and Tuesday, Willa is expected to be a dangerous hurricane when it reaches the coast of Mexico late Tuesday or early Wednesday," the center said.

In its latest advisory, the NHC said Willa was about 230 miles south of Las Islas Marias, Mexico and some 175 miles south-southwest of Cabo Corrientes, Mexico, and was moving north at about  7 mph.

Hurricane-force winds extended outward up to 30 miles from the center and tropical-storm-force winds extend outward up to 90 miles.

A hurricane warning was posted for a stretch of shore between San Blas and Mazatlan. A tropical storm warning was in effect for Playa Perula to San Blas and north of Mazatlan to Bahia Tempehuaya.

Forecasters said Willa is expected to produce storm total rainfall accumulations of 6 to 12 inches, with local amounts up to 18 inches, across portions of western Jalisco, western Nayarit, and southern Sinaloa in Mexico. The rainfall could cause life-threatening flash flooding and landslides. Farther inland, Willa is expected to produce rainfall amount of 2 to 4 inches across portions of Zacateca, Durango, southeast Chihuahua, and Coahuila in Mexico, with local amounts to 6 inches possible. That could cause life-threatening flash flooding.

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