Flash Flood Prediction Program

Message 1’s have been issued for the entire District effective until 9:00pm for the threat of heavy rainfall with a slight chance for severe storms across the District this afternoon and evening.

Storms have initiated along the higher terrain and are expected to move into the District over the next hour. Storm motions are SW to NE between 15-20 mph which could help with point rainfall amounts with erratic storm movement likely along outflow boundaries leading to a better chance for longer lasting moderate to heavy rainfall. Storms may also contain large hail up to 1.0” and gusty winds up to 60mph. Dew points are also still elevated, in the upper 40s to low 50s and will likely help fuel moderate to heavy rainfall leading to some localized flooding.

A couple of rounds of storms will be possibly today, likely decreasing in strength as the evening progresses with off and on showers possible through the overnight. Overnight temperatures will drop to the mid to upper 60s on the plains with upper 50s to low 60s along the foothills.

STORM RAINFALL POTENTIAL AND DURATION: Typical showers/thunderstorms today will produce a trace to 0.25" total in 10-30 minutes. Moderate to strong thunderstorms will produce up to 0.25-0.75” in 10-30 minutes.

WORST CASE SCENARIO: Stationary thunderstorms, or training of thunderstorm cells have the potential to produce up to 1.50” in under 30 minutes.

County	Message	Valid Times	Prime Time
the City of Aurora	1	Current TO 900 PM	400 PM TO 800 PM
Arapahoe County	1	Current TO 900 PM	400 PM TO 800 PM
DIA	1	Current TO 900 PM	400 PM TO 800 PM
Denver County	1	Current TO 900 PM	400 PM TO 800 PM
Adams County	1	Current TO 900 PM	400 PM TO 800 PM
Douglas County	1	Current TO 900 PM	400 PM TO 800 PM
Broomfield County	1	Current TO 900 PM	400 PM TO 800 PM
Jefferson County	1	Current TO 900 PM	400 PM TO 800 PM
Boulder County	1	Current TO 900 PM	400 PM TO 800 PM
Arvada	1	Current TO 900 PM	400 PM TO 800 PM
Wheat Ridge	1	Current TO 900 PM	400 PM TO 800 PM
Lakewood	1	Current TO 900 PM	400 PM TO 800 PM

County-specific Quantitative Precipitation Outlook	Precipitation Time	30-Minute Rainfall and % Probability	Message Potential
Plains
Adams	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Arapahoe	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Boulder	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Broomfield	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Denver	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Douglas	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Jefferson	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Foothills above 6500ft
Boulder	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Douglas	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED
Jefferson	Current TO 900 PM WED	Trace (75%) to 0.25" (50%) to 0.75" (25%)	ISSUED

MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS.