Flash Flood Prediction Program

-	Message 1's have been issued for the entire District and will be valid until 6:00pm then the Message 1's will be upgraded to Message 2's to coincide with the NWS Flash Flood Watch.
-	A cold front is on the approach and is already producing strong thunderstorms over northern Colorado. As the front moves southward thunderstorms are expected to develop behind it becoming strong to severe with the potential to produce extended periods of heavy rainfall that may lead to excessive runoff and possibly flash flooding.
-	Moisture levels are expected to be higher than at any point this season later today and tomorrow and will result in efficient rainfall producing storms. The greatest threat for heavy rain from thunderstorms will be through about midnight then rain showers may be capable of producing up to 1"/hr or higher rainfall rates overnight.

STORM RAINFALL POTENTIAL AND DURATION: Weak thunderstorms will produce 0.2-0.6" in 10-30 minutes. Moderate to strong thunderstorms will have the potential to produce 0.6-1.8" of heavy rain in 10-30 minutes.

WORST CASE SCENARIO: A strong thunderstorm will have the potential to produce up to 3.5" in 45-60 minutes. Storms that persist beyond 60 minutes may produce locally higher amounts.

County	Message	Valid Times	Prime Time
Broomfield County	1	Current TO 600 PM	500 PM TO 600 PM
Jefferson County	1	Current TO 600 PM	500 PM TO 600 PM
Boulder County	1	Current TO 600 PM	500 PM TO 600 PM
Wheat Ridge	1	Current TO 600 PM	500 PM TO 600 PM
Arvada	1	Current TO 600 PM	500 PM TO 600 PM
the City of Aurora	1	Current TO 600 PM	500 PM TO 600 PM
Arapahoe County	1	Current TO 600 PM	500 PM TO 600 PM
DIA	1	Current TO 600 PM	500 PM TO 600 PM
Denver County	1	Current TO 600 PM	500 PM TO 600 PM
Adams County	1	Current TO 600 PM	500 PM TO 600 PM
Douglas County	1	Current TO 600 PM	500 PM TO 600 PM
Lakewood	1	Current TO 600 PM	500 PM TO 600 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Arapahoe	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Boulder	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Broomfield	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Denver	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Douglas	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Jefferson	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Foothills above 6500ft
Boulder	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Douglas	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED
Jefferson	500 PM TO 1159 PM	0.2" (100%) to 0.6" (75%) to 1.8" (50%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.