Bud becomes a major hurricane May 25, 2012 -- Updated 0525 GMT (1325 HKT) A satellite image shows Tropical Storm Bud off southwestern Mexico on Thursday. "Bud is expected to reach the coast of Mexico as a hurricane," an agency says Hurricane and tropical storm warnings are in effect for parts of Mexico's coast Maximum sustained winds are near 115 mph, the National Hurricane Center says Miami, Florida (CNN) -- Bud flexed its muscles as it closed on the southwestern coast of Mexico late Thursday, becoming a major hurricane with winds of 115 mph, the National Hurricane Center said. The Category 3 storm was about 170 miles (270 km) southwest of Manzanillo and about 230 miles (370 km) south of Cabo Corrientes at 8 p.m. (11 p.m. ET) It was moving north-northeast at a rate of about 10 mph. "Some fluctuations in strength are possible tonight and Friday morning before gradual weakening begins by Friday afternoon," the hurricane center said. "However, Bud is still expected to reach the coast of Mexico as a hurricane" late Friday. A hurricane warning has been issued for Manzanillo northwest to Cabo Corrientes, where winds are expected to exceed 39 mph within the next 36 hours and eventually top 74 mph. There are hurricane,and tropical storm watches and warnings in effect for larger swaths of the country, including San Blas and Punta San Telmo, the hurricane center said. The National Hurricane Center warned that Bud is expected to bring 5 to 8 inches of rain along Mexico's southwestern coast, with possible isolated amounts of 12 inches. "These rainfall amounts could produce life-threatening flash floods and mudslides," according to the U.S agency. Swells generated by Bud affected coastal areas on Mexico's southern and southwestern coasts Thursday. They "are likely to cause life-threatening surf and rip current conditions," the hurricane center said. CNN's Mari Ramos, Rob Marciano, Ed Payne and Scott Thompson contributed to this report. A near-normal Atlantic hurricane season is expected this year, with nine to 15 named storms and four to eight hurricanes, says the National Oceanic and Atmospheric Administration. May 25, 2012 -- Updated 0056 GMT (0856 HKT)