First Alert Weather Day: The heaviest rain is yet to come in many Colorado areas

Excess monsoon moisture moving into Colorado on Thursday will increase the threat for flash flooding especially over the wildfire burn areas in the mountains. Because of the chance for heavy downpours, it's a First Alert Weather Day for all of Colorado.

There is a Flash Flood Watch for about three quarters of the state from late morning through late evening on Thursday. The watch includes the entire I-70 mountain corridor and all of southern Colorado.

The large scars left behind by recent wildfires like East Troublesome, Camron Peak, and Grizzly Creek have an "elevated" threat for flash flooding. I-70 through Glenwood Canyon could be forced to close if thunderstorms move near the Grizzly Creek scar.

For Denver and the Front Range, the best chance for thunderstorms producing heavy rain and possible street flooding on Thursday will be after noon and before midnight.

Looking ahead to Friday, more showers and thunderstorms are expected mostly in the afternoon and evening. The overall threat for heavy rain is somewhat lower on Friday so a First Alert Weather Day has not been declared but periods of excessive rain will still be possible.

Temperatures will also stay much cooler than usual on Thursday and Friday with Denver's high temperature only in the upper 70s on Thursday.

For the final weekend of July, plan on warmer temperatures and gradually drier weather. The chance for afternoon thunderstorms in the metro area drop to just 20% on Sunday.