Flash Flood Prediction Program

-	Message 1's have been issued for the entire District valid from 10:30 AM to 10:00 PM. Rain showers are beginning to fill in over the District currently becoming widespread into the afternoon with embedded thunderstorms. Thunderstorms will become more likely after 11:00 AM and will have the potential to produce heavy rainfall.
-	Individual thunderstorm cells will move fairly quickly from SW to NE at 25-30mph helping to lower point rainfall amounts from a single storm. Large thunderstorms or training of thunderstorm cells pose the greatest threat for extended periods of heavy rainfall that could lead to excessive runoff and flash flooding. Persistent/steady moderate rain showers also have the potential to produce rainfall rates of up to 1"/hr which may create some runoff issues in smaller creeks/streams.
-	Shower and thunderstorm activity is expected to continue into the evening with precipitation likely favoring rain showers versus thunderstorms after 8 or 9pm. Additional lighter rain shower activity will continue possible into the overnight period.

STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.4" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.4-1.2" in 10-30 minutes. Persistent/steady moderate rain may produce up to 1.0"/hr rainfall rates.

WORST CASE SCENARIO: A large slow moving thunderstorm or training of moderate to strong thunderstorm cells may produce up to 2.3" in 60-90 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Jefferson County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Broomfield County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Douglas County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Adams County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Denver County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
DIA	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Arapahoe County	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
the City of Aurora	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Arvada	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Wheat Ridge	1	1030 AM TO 1000 PM	1100 AM TO 900 PM
Lakewood	1	1030 AM TO 1000 PM	1100 AM TO 900 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Arapahoe	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Boulder	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Broomfield	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Denver	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Douglas	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Jefferson	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (65%) to 1.2" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (60%) to 1.2" (20%)	ISSUED
Douglas	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (60%) to 1.2" (20%)	ISSUED
Jefferson	Current TO 1000 PM SUN	0.1" (100%) to 0.4" (60%) to 1.2" (20%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.