Tropical storm Irwin weakened a little Wednesday as it moved across the Pacific Ocean toward Baja California, U.S. forecasters said. Packing maximum sustained winds of 40 mph, Irwin was 590 miles west-southwest of Manzanillo Mexico moving east-northeast at 10 mph, the National Hurricane Center in Miami said in its 5 a.m. EDT advisory. No coastal watches or warnings were posted because of Irwin. Forecasters said some increase in Irwin\'s forward speed was likely later in the day followed by a turn toward the east on Thursday and a gradual decrease in speed.