In the midst of a tornado outbreak wreaking havoc across the Plains, the National Weather Service (NWS) has issued a flash flood emergency for the Oklahoma City metro area -- a first, the NWS says.

A tornado was spotted near downtown Oklahoma City and cars were reportedly flipped on a local highway, and now flash flooding is rising as a concern.

"Over 3 inches of rain fell at Will Rodgers World Airport in the span of a single hour on Wednesday. Furthermore, the National Weather Service in Norman, Oklahoma states that 7.10 inches throughout the day, making it the wettest May day on record," weather.com meteorologist Chrissy Warrilow said.

Weather Underground historian Christopher Burt states that the "all-time 24-hour record for Oklahoma City is 8.95 inches, which was set October 19-20, 1983."

According to the NWS, the current flooding situation in OKC will put residents in life-threatening situations for which they may be unprepared.

(MORE: Tornado Outbreak Wreaks Havoc Across Great Plains )

The reason why the NWS added this first-time flash flood emergency to the OKC metro warning is because flood waters now have the potential to reach unprecendented levels and not only threaten homes, but also pose the risk of having "catastrophic impact" in the event of a breeched dam.

According to OG&E, over 7,000 people have already lost power in Oklahoma City Wednesday night.

MORE ON WEATHER.COM: Tornadoes in the Plains, May 6, 2015