Hurricane Greg was picking up strength Thursday as the center passed south of the Socorro Islands off Mexico's west coast, the National Hurricane Center said. Greg, a Category 1 hurricane with maximum sustained winds of 85 mph, was about 320 miles south-southwest of the southern tip of Baja California, Mexico, and moving west-northwest at 18 mph, the center said in its 8 a.m. EDT advisory from Miami. No coastal watches or warnings were in effect. The center said the storm should strengthen Thursday and was expected to begin weakening Friday. Copyright 2011 United Press International, Inc. (UPI). Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent