Miriam -- downgraded to a Category 1 hurricane with maximum sustained winds of 80 mph -- was about 430 miles southwest of the southern tip of Baja California, Mexico, moving northwest at 5 mph, the National Hurricane Center in Miami said in its 11 p.m. EDT advisory.
Miriam is expected to shift toward the northwest Tuesday night and then turn toward the north-northwest by Wednesday, forecasters said. Further gradual weakening is expected during the next 48 hours.
Hurricane-force winds extended as much as 35 miles from the storm's center and tropical storm-force winds extended 105 miles.
Swells generated by Miriam will affect the south and west coasts of the southern and central Baja Peninsula for several days. The swells are likely to cause life-threatening surf and rip current conditions, forecasters said.