(AP) MIAMI (AP) -- Forecasters say Miriam is rapidly weakening and has been downgraded from a hurricane to a tropical storm well off Mexico's Baja California peninsula.The National Hurricane Center in Miami said Miriam had top sustained winds of 70 mph at 5 a.m. EDT Wednesday, down sharply from a day earlier. The storm was centered about 430 miles west-southwest of the southern tip of the Baja peninsula.Miriam is moving northwest at 6 mph. No coastal watches or warnings are in effect and more weakening is expected.In the open Atlantic, Tropical Storm Nadine remains far from land. It is about 530 miles south-southwest of the Azores islands with top sustained winds of about 45 mph. Nadine has been spinning in the Atlantic for more than two weeks.Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.For more information about reprints & permissions, visit our FAQ's. To report corrections and clarifications, contact Standards Editor Brent Jones. For publication consideration in the newspaper, send comments to firstname.lastname@example.org. Include name, phone number, city and state for verification. To view our corrections, go to corrections.usatoday.com.