Flash flood warning issued for Frisco, Plano as storms move south

Drivers in Frisco and Plano faced the most immediate flash-flood risk Tuesday as the National Weather Service warned that low-lying streets, underpasses and drainage-prone areas could quickly take on water before the warning expired at 6 p.m. CDT. The alert covered parts of Collin and Denton counties while a broken line of thunderstorms moved south across North and Central Texas behind a cold front.

The National Weather Service Fort Worth/Dallas office, which handles watches, warnings and forecasts for 46 counties and serves more than 9 million people, said the storm pattern carried locally heavy rainfall and the chance of isolated flash flooding. Forecasters said heavy rain and training thunderstorms could produce a very localized flash flood threat, even as the broader flood risk was expected to be greater farther south in Central Texas.

That kind of setup is one of the most dangerous in North Texas. The Weather Service’s flash-flood climatology says flash flooding kills more people annually than any other type of severe weather, and the danger rises where population density is high and drainage systems were not built to handle rapid runoff. Much of North and Central Texas was also expected to receive at least 1 inch of rain from Wednesday through Friday, with a 60% to 90% chance of that amount.

Frisco urged residents to sign up for CodeRED, its emergency notification system that sends alerts by phone, email and text. The city’s severe-weather guidance says flooding is among the dangerous by-products of thunderstorms that can threaten the community, and it activates outdoor warning sirens when hail reaches 1.5 inches or larger, winds hit 70 mph or greater, or a tornado threatens the area.

The weather system was already producing impacts across the region. A National Weather Service local storm report recorded 0.88-inch hail north of Aubrey in Denton County, a sign that the storm line had begun leaving a mark even before the heaviest rain threat reached its peak. For Collin County commuters, the message was simple: expect fast-changing conditions, watch for water-covered roads, and stay ready for another round of storms as the front kept sliding south.