A flood advisory is in effect for parts of Mecklenburg County tonight, while the National Weather Service said strong thunderstorms hit Union County.Just before 6 p.m., Doppler radar showed a line of thunderstorms extending from UNC Charlotte to four miles southwest of Waxhaw. The storm was moving east at about 13 miles per hour and could affect areas including Mineral Springs, Wingate, Montor and Indian Trail.Earlier tonight, the storm dumped rain on Mecklenburg, Cabarrus and Rowan counties. The weather service warned that flooding could occur in low lying and poorly-drained areas in Mecklenburg. Residents were asked to be on alert for standing water on roads.The weather service advised people in the path of the thunderstorms who are outdoors to avoid isolated high objects, like trees, and to move indoors if possible. Anyone indoors should avoid windows and doors, and stay off the telephone unless it is an emergency. The weather service also suggests unplugging any unnecessary electrical appliances before the storm approaches.Charlotte firefighters said they received about 25 calls for service from 5:30 to 6:30 p.m. and were checking areas across the city for possible flooding. Capt. Rob Brisley said firefighters helped one person get out of high water conditions on Hawthorne Lane, but said no evacuations have been needed in other areas.Brisley said a house on Kanfer Court was struck by lightening, but there were no injuries and no one was displaced. He said it is not a working fire.