The storm system that sowed death and destruction across the South earlier in the weekend plowed toward the Washington region Sunday, with a first wave that prompted tornado warnings and a potential second wave that stoked even greater fears.

For about 15 minutes on Sunday evening, the National Weather Service placed parts of Frederick County and nearby Maryland jurisdictions under a tornado warning.

Before it expired at 6:45 p.m., it gained considerable attention.

Citing the warning, issued for an area around Urbana in Frederick County, one on-air forecaster urged via Twitter: “GO TO BASEMENT NOW!”

Warnings call for action. They usually are issued after a tornado has been spotted by eye or radar.

Even before the warning was issued, most of the Washington region, including the District, was placed under a tornado watch. Tornado watches mean conditions are favorable for thunderstorms that can produce tornadoes.

Forecasters said they expected a second line of storms, potentially more damaging than the first, to push into the region from the west or southwest early Monday morning.

Maryland Gov. Larry Hogan (R) took account of forecasts issued earlier in the day and called for close attention to them.

“Residents should take every possible precaution and stay indoors away from windows during thunderstorms,” the governor said in a statement. He said it was particularly important for mobile devices to be set to receive emergency alerts.

Noting that severe storms occur regularly in Maryland in the spring, he said the state has recorded nearly 100 tornadoes in the past 10 years.

While the tornado watch was in force Sunday night, watch parties were held in the area. They were not to watch storms but to watch the start of the final season of the popular TV show “Game of Thrones.”