By BRIAN K. SULLIVAN
Tropical Storm Karen weakened as it moved northward through the Gulf of Mexico to the US coast, where the system is forecast to make landfall over the weekend with heavy rain and rough seas.
Top sustained winds for Karen, which is no longer expected to become a hurricane, dropped to 50 miles (80 kilometers) per hour, from 60 mph earlier. It was 275 miles south-southeast of Morgan City, Louisiana, moving north-northwest at 9 mph, according to a National Hurricane Center advisory at 12 p.m. Louisiana time.
The environment does not look favorable for significant intensification, with moderate shear expected to continue for the next day or two, Michael Brennan, a senior hurricane specialist at the center in Miami, said.
Wind shear is when winds blow at varying speeds or directions at different altitudes. If the shear in Karens path relaxes, the storm might get a chance to strengthen, Brennan wrote. Winds are pushing the more intense thunderstorms away from Karens center, making it harder for the storm to become more powerful, said Matt Rogers, president of the Commodity Weather Group in Bethesda, Maryland.
A weaker storm means less chance for damage to offshore energy operations in the Gulf, Rogers said. The region is home to 23% of US crude production, 5.6% of gas output and more than 45% of petroleum refining capacity, according to the Energy Department.
About 39% of gas production and almost half of Gulf oil output was closed by the storm, the US Bureau of Safety and Environmental Enforcement said Friday. In all, 185 platforms and 18 rigs were evacuated, accounting for 693,345 bpd of oil and about 1.5 billion cubic feet/day of gas.
Were not expecting any strengthening, were kind of thinking it will stay the same or weaken, said Jared Smith, a meteorologist at MDA Weather Services in Gaithersburg, Maryland.
The hurricane center predicts Karen will clip the southeastern tip of Louisiana late Saturday or early the next day and then go ashore close to Mobile, Alabama. The system may drive tides 3 to 5 feet (1 to 1.5 meters) above normal from the Mississippi to Mobile Bay.
The biggest threat from the storm may be heavy rains and tornadoes as it comes ashore, said Dan Kottlowski, a meteorologist at AccuWeather in State College, Pennsylvania.
Three to 6 inches (8 to 15 centimeters) of rain may fall through the central and eastern Gulf, with some areas receiving as much as 10 inches, according to the center.
Karen may be a depression or a weak tropical storm upon landfall this weekend, but even the strongest models still keep the storm well below damaging threshold levels, Rogers said. Poor Karen is really struggling this morning.
A hurricane watch, meaning storm conditions may arrive in two days, is still in effect from Grand Isle, Louisiana, to west of Destin, Florida. That may be changed to a tropical storm watch or warning later today, according to the center.
In addition, a tropical storm warning is in effect from Grand Isle to Morgan City. A storm watch is in place for New Orleans, Lake Maurepas, Lake Pontchartrain and from Destin to Indian Pass, Florida.
Karen is the 11th named storm of the Atlantic hurricane season, which began June 1 and ends Nov. 30. The system would be the second to hit the US this year. Tropical Storm Andrea make landfall on northwestern Florida in June and then moved up the East Coast.