By BILL MILLER A cold front is heading our way, bringing with it the possibility of strong to severe thunderstorms tonight.There’s a 20 percent chance of thunderstorms during the day, but that increases to 50 percent tonight, according to the National Weather Service.If the storms develop, they would likely be scattered — and possibly severe, said Joe Harris, weather service meteorologist in Fort Worth.Should it rain, it would mark the first significant precipitation since 0.63 of an inch fell at Dallas/Fort Worth Airport on Aug.