Tropical Storm Don temporarily jogged westward Thursday evening but was expected to resume a more northwesterly course across the Gulf of Mexico toward the Texas coast, forecasters said.The storm led to shutdowns of some oil and gas rigs in the Gulf, but it was not expected to gain much force.Jesse Moore, a meteorologist with the National Weather Service in Fort Worth, said hopes that Don would bring rain to North Texas were diminishing."Due to a trend to take the storm further south, the chance of getting any significant rain is decreasing," Moore said at 10:30 p.m. Thursday.The official temperature at DFW Airport hit 100 degrees for the 28th straight day on Friday, one short of second on the all-time list.The forecast calls for highs in the upper 90s on Saturday, but if the temperature makes it to triple digits, the summer of 2011 will move into a tie for second all-time for consecutive 100-degree days, at 29.Either way, Saturday may end up being the coolest day for a while. Temperatures are forecast to be from 104 to 107 through Thursday.At 10 p.m. Thursday, Don was 370 miles southeast of Corpus Christi with maximum sustained winds of 50 mph, according to a National Hurricane Center bulletin. The system was forecast to come ashore near Corpus Christi as a tropical storm late today or early Saturday, the center said.Tropical storm warnings and watches are posted along the Texas coast from Galveston Island to the Mexican border.Drought reliefDon was expected to drop 3 to 5 inches of rain across drought-stricken South Texas and up to 7 inches in isolated areas, according the center."Texas needs rain with a name," state Agriculture Commissioner Todd Staples said in a statement. "Hopefully, this will be just the kickoff of a series of rain events to break the grip of this devastating drought."A weather system becomes tropical when it develops cyclone characteristics and becomes a named tropical storm when its winds reach 39 mph. A storm becomes a hurricane when winds hit 74 mph.Don is encountering dry air in the western Gulf, which along with wind shear may keep it from intensifying before it goes ashore, according to the hurricane center."The intensity guidance is in good agreement that Don will make landfall as a tropical storm and not as hurricane," according to a hurricane center forecast analysis.The storm is expected to fall apart in about three days.Impact on industryStorms are watched closely because they are a threat to oil and natural gas interests in the Gulf, home to 31 percent of U.S. oil output and 7 percent of natural gas production.Coastal refineries account for 7.61 million barrels a day, or 42 percent of U.S. capacity.Don has forced the closing of about 6.8 percent of oil production and 2.8 percent of gas output from the Gulf, according to the Bureau of Ocean Energy Management, Regulation and Enforcement.Northern Natural Gas was shutting down production from its Matagorda Offshore Pipeline System in the Gulf that extends from Mustang Island to Tivoli, according to a notice for customers.BP Plc. said it halted production at its Atlantis platform, and Anadarko Petroleum evacuated workers and prepared to shut down several facilities. Royal Dutch Shell closed its Perdido Spar platform.Shell, Chevron Corp. and Apache Corp. said they were removing nonessential workers from some operations.The U.S. hasn't had a direct hit from a tropical storm since Bonnie went ashore in Florida in July 2010. The last hurricane to make landfall in the U.S. was Ike, a Category 2 storm, in Texas in 2008.Staff writer Marty Sabota contributed to this report.