Flash Flood Prediction Program

Message 1’s have been issued for the entire District and will be valid until 9:00pm this evening.

Storm have initiated along the higher terrain at this time and should move into the District in the next hour or two. Currently temperatures have been fairly suppressed with upper 50’s to low 60’s across the District. These cooler temperatures could help limit storm strength heading into this afternoon, however, with this approaching disturbance, combined with dew points currently in the low 50’s, there will be a good chance for moderate to heavy rainfall this afternoon and evening even out of weak to moderate thunderstorms. The best chance for showers and thunderstorms will be from 1-9pm with lingering rain showers possible through midnight.

Storm motions today will continue from the S/SW to N/NE for the most part, with additional storms likely forming along outflow boundaries. These outflow storms will likely have the highest chance of bringing localized heavy rainfall as the storm movements will be non-existent at times. There will be multiple rounds of storms possible today as well, however the initial round should have highest chance for impactful rain showers, with additional rounds likely becoming much weaker into the evening hours.

STORM RAINFALL POTENTIAL AND DURATION: Weak to moderate thunderstorms will produce 0.1-0.3” of rain in 10-30 minutes. Strong thunderstorms will have the potential to produce rainfall rates of 0.3-0.8” in 10-30 minutes.

WORST CASE SCENARIO: A nearly stationary strong thunderstorm may result in up to 1.6” of rain in 45-75 minutes.

County	Message	Valid Times	Prime Time
Boulder County	1	1200 PM TO 900 PM	100 PM TO 830 PM
Jefferson County	1	1200 PM TO 900 PM	100 PM TO 830 PM
Broomfield County	1	1200 PM TO 900 PM	100 PM TO 830 PM
Douglas County	1	1200 PM TO 900 PM	100 PM TO 830 PM
Adams County	1	1200 PM TO 900 PM	100 PM TO 830 PM
Denver County	1	1200 PM TO 900 PM	100 PM TO 830 PM
DIA	1	1200 PM TO 900 PM	100 PM TO 830 PM
Arapahoe County	1	1200 PM TO 900 PM	100 PM TO 830 PM
the City of Aurora	1	1200 PM TO 900 PM	100 PM TO 830 PM
Arvada	1	1200 PM TO 900 PM	100 PM TO 830 PM
Wheat Ridge	1	1200 PM TO 900 PM	100 PM TO 830 PM
Lakewood	1	1200 PM TO 900 PM	100 PM TO 830 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Arapahoe	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Boulder	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Broomfield	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Denver	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Douglas	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Jefferson	1200 PM TO 900 PM	0.1" (90%) to 0.3" (60%) to 0.8" (20%)	ISSUED
Foothills above 6500ft
Boulder	1200 PM TO 900 PM	0.1" (90%) to 0.3" (80%) to 0.8" (40%)	ISSUED
Douglas	1200 PM TO 900 PM	0.1" (90%) to 0.3" (80%) to 0.8" (40%)	ISSUED
Jefferson	1200 PM TO 900 PM	0.1" (90%) to 0.3" (80%) to 0.8" (40%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.