DALLAS (AP) — Some flights were delayed or canceled in Texas on Thursday after a line of thunderstorms began moving across parts of the state in a system the National Weather Service forecast would bring strong winds, hail and possible tornadoes could bring about.

More than 100 flights were delayed and dozens more were canceled at Dallas Fort Worth International Airport on Thursday. Delays and thunderstorm-related cancellations were also reported at Love Field in Dallas and George Bush Intercontinental Airport in Houston, according to FlightAware, an aviation company that tracks flights around the world.

The National Weather Service has issued a tornado warning for several counties in southeast Texas, including the Houston area, meaning conditions are favorable for possible tornadoes. The watch should remain in effect until Thursday at 7:15 p.m.

The greatest weather risk was forecast for a section of Texas east of Dallas between Houston and parts of southern Arkansas and western and northern Louisiana, said Brian Hurley, a meteorologist at the National Weather Service’s Weather Prediction Center.

“There is a possibility of one or more tornadoes with this risk, but the primary risk will be high winds and hail,” Hurley said, adding that he expected wind gusts generally between 60 and 80 miles per hour (96 to 128 km/h ) expect ) and hailstones with a diameter of at least 2.5 centimeters.

Hurley said the storms would likely move into southern Arkansas and western and northern Louisiana after dark, posing a potentially dangerous situation for leisure travelers.

“People can’t see much and may not be as aware of the weather,” he said.