A hurricane warning means hurricane conditions are expected within 24 hours . NEW : Hurricane warning issued for the southern Jimena peninsula . The Category 4 storm is centered off the Pacific Ocean , traveling northwest at 155 mph . Brown 's sustained winds near 10 mph , but forecasters expect it to pick up speed .
NEW : Hurricane warning issued for the southern Jimena peninsula . The Category 4 storm is centered off the Pacific Ocean , traveling northwest at 155 mph . Brown 's sustained winds near 10 mph , but forecasters expect it to pick up speed .