Time: 957 AM Sun May 24, 2020 Forecaster: Brad Simmons

Flash Flood Prediction Program


We have determined that street and small stream flooding is possible in the following counties: Boulder (City of Boulder affected, Four Mile Burn Area affected), Jefferson, Broomfield, Douglas, Adams, Denver, Arapahoe
including: DIA, the City of Aurora, Arvada, Wheat Ridge, Lakewood
from: 1030 AM to 1000 PM.
Prime time for flooding: 1100 AM to 900 PM.
Forecast rainfall: Moderate and strong thunderstorms will have the potential to produce rainfall amounts of 0.4-1.2" in 10-30 minutes. A large, slow moving, strong thunderstorm or training of thunderstorm cells may result in up to 2.3" of rainfall in 60-90 minutes. Persistent/steady rain showers also have the potential to produce up to 1"/hr rainfall rates.
The most likely areas to be impacted by flooding are:

X Mountain streams & floodplains; road crossings; canyon roads & highways; recreational trails; adjacent open space areas/campgrounds/parks; fishing access points & stream reaches; buildings near streams; utilities

X Urban streams/gulches; road crossings; recreational trails; adjacent open space areas/campgrounds/parks; floodplain properties; utilities

X Urban streets, intersections, low lying areas, known trouble spots

X Mountain locations subject to mud/rock/debris slide

Additional Information: Strong thunderstorms may also produce frequent cloud-to-ground lightning, gusty straight-line winds and large hail.

This message is not intended for public dissemination. Please pass this information along to affected emergency response organizations (police, fire, public works, etc.) within your area.

Also, please take appropriate actions to prepare for possible flooding.

Further information will be provided to you as it becomes available.