(Updates with total shut-ins as of Saturday, storm position)
HOUSTON, June 6 (Reuters) - Tropical Storm Cristobal moved through the U.S. Gulf of Mexico on Saturday carrying strong winds and heavy rains that prompted the evacuation of a coastal Louisiana community and dozens of offshore oil platforms.
Cristobal, packing winds of 50 miles per hour (85 km), is expected to strengthen somewhat before making landfall late Sunday along the Louisiana coast, according to the U.S. National Hurricane Center (NHC).
Grand Isle, a barrier island on the Louisiana coast, was under a mandatory evacuation, ahead of a storm surge expected to be as much as 2 feet to 4 feet (1.2 meters) in an area between Morgan City, Louisiana, and the mouth of the Mississippi River.
The early season storm is not expected to become a hurricane but its heavy rains could cause flash flooding in the central Gulf Coast. It could drop between 4-inches and 8-inches (20 cm) of rain along the Louisiana coast, NHC forecasters said.
Oil companies on Saturday had evacuated 177 Gulf of Mexico offshore facilities and shut-in some 616,000 barrels per day of oil and 853 million cubic feet per day of natural gas output, the Bureau of Safety and Environmental Enforcement said.
Traders pushed spot gasoline prices higher on Friday, fearing storm-related production losses.
The nine Louisiana oil refineries in the path of Cristobal plan to keep operating through rains and high winds expected to sweep over an area between Baton Rouge and New Orleans, according to people familiar with the matter.
Combined capacity of the nine refineries is about 12% of the U.S. national total of 18.8 million barrels per day (bpd). U.S. Gulf of Mexico platforms account for about 1.93 million bpd, or about 15% of the U.S. total daily oil production.
Exxon Mobil, Royal Dutch Shell Plc and PBF Energy prepared their Louisiana refineries to keep operating, the people said.
The storm on Saturday afternoon was about 310 miles south of the mouth of the Mississippi River and traveling north at about 12 mph, according to the NHC.
Reporting by Erwin Seba and Gary McWilliams; editing by Diane Craft
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