Heavy rain and strong winds moved through the Southeast Thursday, knocking out power for thousands and flooding streets in North Carolina and Florida.

Warm air, loaded with tropical moisture, had been streaming north ahead of a slow moving low pressure system, weather.com meteorologist Chrissy Warrilow explained.

"As a cold front associated with the low pushes east, thunderstorms form along the front. However, the entire complex is not moving very fast, so thunderstorms 'train,' or move over areas that have already received heavy rain, and the result can be very serious flash flooding."

Flooding could be found along roadways in Hialeah, Doral and several coastal communities in northeastern Miami-Dade and Broward Counties, according to CBS Miami.

Traffic had slowed to a crawl in parts of Hialeah, where the storm dropped 6 inches of rain Thursday afternoon. "Sometimes you can see the water all the way to the tires, above the tires on some cars," a driver told CBS Miami. Prior to the flooding, the Miami area was also under a tornado warning.

(MORE: Tornado Touches Down in Miami)

As strong storms moved through parts of North Carolina, Wake County was temporarily under a flash flood warning Thursday evening, News Observer reports. In Durham, initial reports showed trees and power lines were down in the area of Hope Valley Road on the city's south side. Some streets were blocked by trees. Duke Energy reported that more than 5,000 customers were without power in Durham Thursday evening.

Ryan Ellis of the National Weather Service told the Associated Press there were also reports of flooding in Chapel Hill and Raleigh.