A flood warning is in effect for parts of Baltimore City and Baltimore County. The National Weather Service issued the warning after heavy rain Thursday night from severe thunderstorms 

The flood warning is in effect until 12:15 a.m. Friday, Aug. 23.

Up to 2 inches of rain had fallen before 9:30 p.m., weather officials said, and broadcast media reported after 10 p.m. that there was already flooding on some Baltimore streets.

More showers moving across the city may add 0.25 to 0.5 inch rain atop the 1 to 2 inches that have already fallen in some areas, according to the warning, which stated: "This could prolong the flood threat."

During a flood warning, flooding is imminent or occurring. Drivers should turn around if they come across flooded roads, and pedestrians should not attempt to walk through flood waters. People should be particularly careful at night when it is hard to see and vigilant in low-lying spots and those with poor drainage, which are more prone to flooding.

According to the warning, these areas may experience flooding: Baltimore, Pikesville, Middle River, North Point State Park, Back River, Dundalk, Towson, Catonsville, Essex, Woodlawn, Parkville, Carney, Perry Hall, Lochearn, Arbutus, Rosedale, Rossville, Brooklyn Park, White Marsh and Edgemere.