Severe thunderstorm warning hits Rockwall County overnight, hail and flooding risk

Rockwall County drivers heading out before sunrise faced a severe thunderstorm warning until 4:00 a.m., with radar-indicated half-dollar-size hail, continuous cloud-to-ground lightning and heavy rain that could trigger flash flooding along key roads.

At 3:00 a.m. CDT, the National Weather Service said the storm was near Richardson and moving northeast at 25 mph. The warning covered northwestern Rockwall County, along with southeastern Denton County, Collin County and northeastern Dallas County, putting early commuters in the path of a fast-moving line of storms before the morning rush.

The agency said vehicle damage was possible from the hail, a particular concern for anyone parked outside overnight or traveling exposed routes toward Dallas, Garland, Richardson, Plano, Sachse, Murphy, Parker, Wylie, Lucas, Allen and Lavon. Heavy rainfall was also a concern on Interstate 35E between mile markers 437 and 444, where water can build quickly if thunderstorms stall or keep training over the same area.

Residents were urged to get inside a sturdy structure, stay away from windows and avoid driving through flooded roadways. That advice mattered across Rockwall County’s 127.2 square miles, where a 2024 Census Bureau estimate put the population at 137,044, up sharply from 107,819 in the 2020 census. In a county that fast-growing, overnight weather can affect thousands of homes, early-shift workers and families trying to get children ready for school and day care before dawn.

Forecasters said the broader pattern across North and Central Texas stayed unsettled through Memorial Day weekend. Scattered showers and thunderstorms remained possible, with a few stronger storms bringing gusty winds, small hail, frequent lightning and a low flooding threat where storms repeatedly moved over the same locations.

The National Weather Service Fort Worth office also maintains Rockwall County tornado climatology and a North Texas past-events archive, a reminder that severe weather is a recurring threat in this part of the metroplex. For Rockwall County residents, the immediate concern overnight was simple: stay inside, keep off flooded roads and watch the next round of storms as the region headed into the holiday weekend.