A flash flood watch is in effect for metro Denver, as thunderstorms roll in with the potential for up to 2 inches of rain in less than an hour on Monday afternoon.

The flood watch zone in the metro extends from Brighton in the north to Larkspur in the south, and includes Aurora, Denver, Highlands Ranch, Littleton and Denver International Airport. The National Weather Service projects that flooding could occur starting at 2 p.m. and continue until 9 p.m. Monday.

Thunderstorms will again move from the mountains to the plains this afternoon and evening. There’s a greater threat of heavy rainfall and flash flooding today, especially over the recent burn areas, the Denver area, Palmer Divide, and parts of the eastern plains. #cowx pic.twitter.com/a8MJYPArq1

— NWS Boulder (@NWSBoulder) August 12, 2024

Flooding of underpasses, streams and low-lying urban areas is possible.

Heavy rain could impact areas beyond the metro Monday afternoon, and the weather service said the worst of it — with a potential of more than 3 to 4 inches of rain — is expected to hit Lincoln and Elbert counties, among other areas on the Eastern Plains. The Palmer Divide, north of Colorado Springs, is also in the path of storms.

Rockslides, with debris in flow, could occur in recent wildfire burn scars, including those created by the recent Alexander Mountain and Quarry fires.

“You should monitor later forecasts and be prepared to take action (e.g. move to higher ground and avoid low-lying areas) should Flash Flood Warnings be issued,” weather service meteorologists warned Monday.

Originally Published: August 12, 2024 at 2:06 p.m.