Flash Flood Prediction Program

-	Message 1's have been issued for the entire District and will be valid until 9pm this evening.
-	Thunderstorms are developing over the higher terrain currently and will be moving from NW to SE onto the plains over the next few hours. Strong thunderstorms will be capable of producing brief heavy rainfall that may lead to excessive runoff. Fast storm motions will keep the heavy rainfall brief, in the 5-15 minute range from most storms but training of thunderstorm cells may result in longer duration of heavy rain.
-	Strong thunderstorms also have a high likelihood of becoming severe with large hail and gusty straight-line winds being the primary threats but a very isolated tornado cannot be ruled out.

STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will have the potential to produce 0.3-0.9" in 10-30 mintues. Supplemental QPF is available at https://qpf.udfcd.org

WORST CASE SCENARIO: A large, slower moving thunderstorm or training of thunderstorm cells may produce rainfall amounts of up to 1.6" in 45-60 minutes.

County	Message	Valid Times	Prime Time
Arapahoe County	1	Current TO 900 PM	300 PM TO 800 PM
DIA	1	Current TO 900 PM	300 PM TO 800 PM
Denver County	1	Current TO 900 PM	300 PM TO 800 PM
Adams County	1	Current TO 900 PM	300 PM TO 800 PM
Douglas County	1	Current TO 900 PM	300 PM TO 800 PM
Boulder County	1	Current TO 900 PM	230 PM TO 800 PM
Jefferson County	1	Current TO 900 PM	230 PM TO 800 PM
Broomfield County	1	Current TO 900 PM	300 PM TO 800 PM
the City of Aurora	1	Current TO 900 PM	300 PM TO 800 PM
Arvada	1	Current TO 900 PM	300 PM TO 800 PM
Wheat Ridge	1	Current TO 900 PM	300 PM TO 800 PM
Lakewood	1	Current TO 900 PM	300 PM TO 800 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 900 PM SUN	0.1" (75%) to 0.3" (60%) to 0.9" (15%)	ISSUED
Arapahoe	Current TO 900 PM SUN	0.1" (80%) to 0.3" (65%) to 0.9" (20%)	ISSUED
Boulder	Current TO 900 PM SUN	0.1" (85%) to 0.3" (65%) to 0.9" (20%)	ISSUED
Broomfield	Current TO 900 PM SUN	0.1" (75%) to 0.3" (60%) to 0.9" (15%)	ISSUED
Denver	Current TO 900 PM SUN	0.1" (75%) to 0.3" (60%) to 0.9" (15%)	ISSUED
Douglas	Current TO 900 PM SUN	0.1" (80%) to 0.3" (65%) to 0.9" (20%)	ISSUED
Jefferson	Current TO 900 PM SUN	0.1" (80%) to 0.3" (65%) to 0.9" (20%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM SUN	0.1" (90%) to 0.3" (75%) to 0.9" (15%)	ISSUED
Douglas	Current TO 900 PM SUN	0.1" (90%) to 0.3" (75%) to 0.9" (15%)	ISSUED
Jefferson	Current TO 900 PM SUN	0.1" (90%) to 0.3" (75%) to 0.9" (15%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.